diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index 7908617..0296b44 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -14,7 +14,15 @@
       <option name="DECONSTRUCTION_LIST_WRAP" value="5" />
       <option name="MULTI_CATCH_TYPES_WRAP" value="0" />
     </JavaCodeStyleSettings>
+    <TypeScriptCodeStyleSettings version="0">
+      <option name="SPACES_WITHIN_OBJECT_LITERAL_BRACES" value="true" />
+      <option name="SPACES_WITHIN_IMPORTS" value="true" />
+    </TypeScriptCodeStyleSettings>
     <codeStyleSettings language="JAVA">
+      <option name="KEEP_BLANK_LINES_IN_DECLARATIONS" value="1" />
+      <option name="KEEP_BLANK_LINES_IN_CODE" value="1" />
+      <option name="KEEP_BLANK_LINES_BETWEEN_PACKAGE_DECLARATION_AND_HEADER" value="1" />
+      <option name="KEEP_BLANK_LINES_BEFORE_RBRACE" value="0" />
       <option name="ALIGN_MULTILINE_PARAMETERS_IN_CALLS" value="true" />
       <option name="ALIGN_MULTILINE_ARRAY_INITIALIZER_EXPRESSION" value="true" />
       <option name="CALL_PARAMETERS_WRAP" value="5" />
@@ -30,6 +38,10 @@
       <option name="ARRAY_INITIALIZER_WRAP" value="5" />
       <option name="ARRAY_INITIALIZER_LBRACE_ON_NEXT_LINE" value="true" />
       <option name="ARRAY_INITIALIZER_RBRACE_ON_NEXT_LINE" value="true" />
+      <option name="IF_BRACE_FORCE" value="3" />
+      <option name="DOWHILE_BRACE_FORCE" value="3" />
+      <option name="WHILE_BRACE_FORCE" value="3" />
+      <option name="FOR_BRACE_FORCE" value="3" />
       <option name="KEEP_BUILDER_METHODS_INDENTS" value="true" />
     </codeStyleSettings>
   </code_scheme>
diff --git a/lombok.config b/lombok.config
new file mode 100644
index 0000000..5ffcbcb
--- /dev/null
+++ b/lombok.config
@@ -0,0 +1,9 @@
+config.stopBubbling = true
+
+# Required for NullAway to work
+lombok.addLombokGeneratedAnnotation = true
+
+# Copy JSpecify annotations to generated code (constructors, getters, setters)
+lombok.copyableAnnotations += org.jspecify.annotations.Nullable
+lombok.copyableAnnotations += org.jspecify.annotations.NonNull
+lombok.addNullAnnotations = jspecify
diff --git a/pom.xml b/pom.xml
index 6aef6c4..1d3540c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>4.0.0</version>
+        <version>4.0.1</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
 
@@ -16,6 +17,8 @@
 
     <properties>
         <java.version>25</java.version>
+        <errorprone.version>2.46.0</errorprone.version>
+        <nullaway.version>0.12.15</nullaway.version>
     </properties>
 
     <dependencyManagement>
@@ -23,7 +26,12 @@
             <dependency>
                 <groupId>it.aboutbits</groupId>
                 <artifactId>spring-boot-toolbox</artifactId>
-                <version>2.0.0</version>
+                <version>2.1.0-RC1</version>
+            </dependency>
+            <dependency>
+                <groupId>it.aboutbits</groupId>
+                <artifactId>archunit-toolbox</artifactId>
+                <version>1.0.0-RC1</version>
             </dependency>
         </dependencies>
     </dependencyManagement>
@@ -72,6 +80,26 @@
             <artifactId>datafaker</artifactId>
             <version>2.5.3</version>
         </dependency>
+
+        <!-- https://mvnrepository.com/artifact/com.tngtech.archunit/archunit-junit5 -->
+        <dependency>
+            <groupId>com.tngtech.archunit</groupId>
+            <artifactId>archunit-junit5</artifactId>
+            <version>1.4.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.tngtech.archunit</groupId>
+            <artifactId>archunit-junit5-api</artifactId>
+            <version>1.4.1</version>
+            <scope>compile</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>it.aboutbits</groupId>
+            <artifactId>archunit-toolbox</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -89,7 +117,36 @@
                             <artifactId>lombok</artifactId>
                             <version>${lombok.version}</version>
                         </path>
+                        <path>
+                            <groupId>com.google.errorprone</groupId>
+                            <artifactId>error_prone_core</artifactId>
+                            <version>${errorprone.version}</version>
+                        </path>
+                        <path>
+                            <groupId>com.uber.nullaway</groupId>
+                            <artifactId>nullaway</artifactId>
+                            <version>${nullaway.version}</version>
+                        </path>
                     </annotationProcessorPaths>
+                    <compilerArgs>
+                        <arg>-Amapstruct.unmappedTargetPolicy=ERROR</arg>
+                        <arg>-XDcompilePolicy=simple</arg>
+                        <arg>--should-stop=ifError=FLOW</arg>
+                        <!-- @formatter:off -->
+                        <arg>-Xplugin:ErrorProne -XepDisableAllChecks -XepOpt:NullAway:AnnotatedPackages=it.aboutbits.springboot.testing -XepOpt:NullAway:JSpecifyMode=true -Xep:NullAway:ERROR -XepOpt:NullAway:ExcludedFieldAnnotations=org.mockito.InjectMocks,org.mockito.Mock</arg>
+                        <!-- @formatter:on -->
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
+                        <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
+                        <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
+                    </compilerArgs>
+                    <fork>true</fork>
                 </configuration>
             </plugin>
             <plugin>
diff --git a/src/main/java/it/aboutbits/springboot/testing/.gitkeep b/src/main/java/it/aboutbits/springboot/testing/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/src/main/java/it/aboutbits/springboot/testing/persistence/PersistenceAssert.java b/src/main/java/it/aboutbits/springboot/testing/persistence/PersistenceAssert.java
index e15ab6b..3194297 100644
--- a/src/main/java/it/aboutbits/springboot/testing/persistence/PersistenceAssert.java
+++ b/src/main/java/it/aboutbits/springboot/testing/persistence/PersistenceAssert.java
@@ -6,8 +6,8 @@
 import it.aboutbits.springboot.toolbox.type.identity.Identified;
 import jakarta.persistence.EntityManager;
 import lombok.AccessLevel;
-import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.Collection;
 import java.util.List;
@@ -18,6 +18,7 @@
 import static it.aboutbits.springboot.toolbox.util.CollectUtil.collectToSet;
 import static org.assertj.core.api.Assertions.assertThat;
 
+@NullMarked
 public final class PersistenceAssert {
     private PersistenceAssert() {
     }
@@ -28,44 +29,32 @@ private static EntityManager getEntityManager() {
 
     @SuppressWarnings("unused")
     public static <ID extends EntityId<?>, E extends Identified<ID> & ChangeAware, M extends Identified<ID> & ChangeAware> WriteOperationAsserter<ID, E, M> assertThatEntity(
-            @NonNull E before,
-            @NonNull Class<M> modelClass
+            E before,
+            Class<M> modelClass
     ) {
         return new WriteOperationAsserter<>(getEntityManager(), List.of(before), modelClass);
     }
 
     @SuppressWarnings("unused")
     public static <ID extends EntityId<?>, E extends Identified<ID> & ChangeAware, M extends Identified<ID> & ChangeAware> WriteOperationAsserter<ID, E, M> assertThatEntity(
-            @NonNull Collection<E> before,
-            @NonNull Class<M> modelClass
+            Collection<E> before,
+            Class<M> modelClass
     ) {
         return new WriteOperationAsserter<>(getEntityManager(), before, modelClass);
     }
 
-    /**
-     * @deprecated Use {@link #assertThatEntityId(EntityId, Class)} instead.
-     */
-    @Deprecated
-    @SuppressWarnings("unused")
-    public static <ID extends EntityId<?>, M extends Identified<ID>> WriteOperationIdAsserter<ID, M> assertThatEntity(
-            @NonNull ID id,
-            @NonNull Class<M> modelClass
-    ) {
-        return new WriteOperationIdAsserter<>(getEntityManager(), List.of(id), modelClass);
-    }
-
     @SuppressWarnings("unused")
     public static <ID extends EntityId<?>, M extends Identified<ID>> WriteOperationIdAsserter<ID, M> assertThatEntityId(
-            @NonNull ID id,
-            @NonNull Class<M> modelClass
+            ID id,
+            Class<M> modelClass
     ) {
         return new WriteOperationIdAsserter<>(getEntityManager(), List.of(id), modelClass);
     }
 
     @SuppressWarnings("unused")
     public static <ID extends EntityId<?>, M extends Identified<ID>> WriteOperationIdAsserter<ID, M> assertThatEntityId(
-            @NonNull Collection<ID> id,
-            @NonNull Class<M> modelClass
+            Collection<ID> id,
+            Class<M> modelClass
     ) {
         return new WriteOperationIdAsserter<>(getEntityManager(), id, modelClass);
     }
@@ -154,6 +143,8 @@ public void hasBeenUpdatedInDatabase() {
 
             for (var savedInstance : savedInstances) {
                 var originalEntity = originalByIdMap.get(savedInstance.getId());
+                Objects.requireNonNull(originalEntity);
+
                 assertThat(originalEntity).isNotNull();
 
                 assertThat(
@@ -177,6 +168,7 @@ public void hasNotChangedInDatabase() {
 
             for (var savedInstance : savedInstances) {
                 var originalEntity = originalByIdMap.get(savedInstance.getId());
+                Objects.requireNonNull(originalEntity);
 
                 assertThat(savedInstance).isNotNull();
                 assertThat(originalEntity).isNotNull();
diff --git a/src/main/java/it/aboutbits/springboot/testing/spring/BeanAccessor.java b/src/main/java/it/aboutbits/springboot/testing/spring/BeanAccessor.java
index 267e8d9..2e9accf 100644
--- a/src/main/java/it/aboutbits/springboot/testing/spring/BeanAccessor.java
+++ b/src/main/java/it/aboutbits/springboot/testing/spring/BeanAccessor.java
@@ -1,15 +1,18 @@
 package it.aboutbits.springboot.testing.spring;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.stereotype.Component;
 
 @Component
+@NullMarked
 public class BeanAccessor implements ApplicationContextAware {
+    @Nullable
     private static ApplicationContext applicationContext;
 
-    public static <T> T getBean(@NonNull Class<T> clazz) {
+    public static <T> T getBean(Class<T> clazz) {
         if (applicationContext == null) {
             throw new IllegalStateException("ApplicationContext is not set. Did you @EnableBeanAccessor?");
         }
@@ -17,7 +20,7 @@ public static <T> T getBean(@NonNull Class<T> clazz) {
     }
 
     @Override
-    public void setApplicationContext(@NonNull ApplicationContext applicationContext) {
+    public void setApplicationContext(ApplicationContext applicationContext) {
         BeanAccessor.applicationContext = applicationContext;
     }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/testdata/base/AllTestDataReader.java b/src/main/java/it/aboutbits/springboot/testing/testdata/base/AllTestDataReader.java
index bd3e6b4..648391d 100644
--- a/src/main/java/it/aboutbits/springboot/testing/testdata/base/AllTestDataReader.java
+++ b/src/main/java/it/aboutbits/springboot/testing/testdata/base/AllTestDataReader.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.testdata.base;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.Comparator;
 import java.util.HashSet;
@@ -9,17 +9,22 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 
+@SuppressWarnings({"java:S119"})
+@NullMarked
 public abstract class AllTestDataReader<ITEM> {
+    @SuppressWarnings("unused")
     public ITEM returnFirst() {
-        return (ITEM) this.returnAll().getFirst();
+        return this.returnAll().getFirst();
     }
 
+    @SuppressWarnings("unused")
     public List<ITEM> returnAll() {
         return this.fetch();
     }
 
     @SafeVarargs
-    public final List<ITEM> returnSorted(@NonNull Comparator<ITEM>... comparators) {
+    @SuppressWarnings("unused")
+    public final List<ITEM> returnSorted(Comparator<ITEM>... comparators) {
         if (comparators.length == 0) {
             throw new IllegalArgumentException("At least one comparator must be provided");
         }
@@ -33,8 +38,8 @@ public final List<ITEM> returnSorted(@NonNull Comparator<ITEM>... comparators) {
     }
 
     @SafeVarargs
-    @SuppressWarnings("unchecked")
-    public final <U extends Comparable<? super U>> List<ITEM> returnSorted(@NonNull Function<ITEM, ? extends Comparable<?>>... comparators) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public final <U extends Comparable<? super U>> List<ITEM> returnSorted(Function<ITEM, ? extends Comparable<?>>... comparators) {
         if (comparators.length == 0) {
             throw new IllegalArgumentException("At least one comparator must be provided");
         }
@@ -47,22 +52,24 @@ public final <U extends Comparable<? super U>> List<ITEM> returnSorted(@NonNull
         return returnAll().stream().sorted(combinedComparator).toList();
     }
 
-    public <U extends Comparable<? super U>> AllAndFiltered<ITEM> returnFiltered(@NonNull Predicate<ITEM> predicate) {
+    @SuppressWarnings("unused")
+    public <U extends Comparable<? super U>> AllAndFiltered<ITEM> returnFiltered(Predicate<ITEM> predicate) {
         var all = this.returnAll();
-        return new AllAndFiltered<ITEM>(
+        return new AllAndFiltered<>(
                 all,
                 all.stream().filter(predicate).toList(),
                 all.stream().filter(item -> !predicate.test(item)).toList()
         );
     }
 
+    @SuppressWarnings("unused")
     public Set<ITEM> returnSet() {
         return new HashSet<>(this.returnAll());
     }
 
     protected abstract List<ITEM> fetch();
 
-    public record AllAndFiltered<T>(@NonNull List<T> all, @NonNull List<T> filtered, @NonNull List<T> other) {
+    public record AllAndFiltered<T>(List<T> all, List<T> filtered, List<T> other) {
 
     }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/testdata/base/FakerExtended.java b/src/main/java/it/aboutbits/springboot/testing/testdata/base/FakerExtended.java
index dc9408d..3fbfb3c 100644
--- a/src/main/java/it/aboutbits/springboot/testing/testdata/base/FakerExtended.java
+++ b/src/main/java/it/aboutbits/springboot/testing/testdata/base/FakerExtended.java
@@ -2,17 +2,18 @@
 
 import it.aboutbits.springboot.toolbox.type.ScaledBigDecimal;
 import it.aboutbits.springboot.toolbox.type.identity.EntityId;
-import lombok.NonNull;
 import net.datafaker.Faker;
 import net.datafaker.service.FakeValuesService;
 import net.datafaker.service.FakerContext;
 import net.datafaker.service.RandomService;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.Locale;
 import java.util.Random;
 import java.util.function.Function;
 import java.util.function.LongFunction;
 
+@NullMarked
 public class FakerExtended extends Faker {
     public FakerExtended() {
         super();
@@ -38,7 +39,7 @@ public FakerExtended(FakeValuesService fakeValuesService, FakerContext context)
         super(fakeValuesService, context);
     }
 
-    public <T extends Enum<?>> T randomEnumValue(@NonNull Class<T> enumClass) {
+    public <T extends Enum<?>> T randomEnumValue(Class<T> enumClass) {
         var values = enumClass.getEnumConstants();
         if (values.length == 0) {
             throw new IllegalArgumentException("Enum class must have at least one value");
@@ -46,19 +47,19 @@ public <T extends Enum<?>> T randomEnumValue(@NonNull Class<T> enumClass) {
         return values[this.random().nextInt(values.length)];
     }
 
-    public <T extends EntityId<Long>> T randomEntityId(@NonNull LongFunction<T> constructor) {
+    public <T extends EntityId<Long>> T randomEntityId(LongFunction<T> constructor) {
         return constructor.apply(
                 super.random().nextInt(9999999)
         );
     }
 
-    public <T extends EntityId<String>> T randomEntityId(@NonNull Function<String, T> constructor) {
+    public <T extends EntityId<String>> T randomEntityId(Function<String, T> constructor) {
         return constructor.apply(
                 super.internet().uuid()
         );
     }
 
-    public String unique(@NonNull String value) {
+    public String unique(String value) {
         return value + "_" + super.random().nextInt(9999999);
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java b/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
index d945982..208ec51 100644
--- a/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
+++ b/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
@@ -1,7 +1,7 @@
 package it.aboutbits.springboot.testing.testdata.base;
 
-import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -10,26 +10,30 @@
 import java.util.function.ObjIntConsumer;
 import java.util.function.UnaryOperator;
 
-@SuppressWarnings("unchecked")
+@SuppressWarnings({"java:S119"})
 @Slf4j
+@NullMarked
 public abstract class ModifiableTestDataCreator<CREATOR extends ModifiableTestDataCreator<CREATOR, ITEM, PARAMETER>, ITEM, PARAMETER> extends TestDataCreator<ITEM> {
+    @SuppressWarnings("unused")
     protected static final FakerExtended FAKER = new FakerExtended();
 
     private boolean mutatorSet = false;
     private boolean mutatorCalled = false;
 
-    protected BiFunction<PARAMETER, Integer, PARAMETER> parameterMutator = (parameter, index) -> {
+    protected BiFunction<PARAMETER, Integer, PARAMETER> parameterMutator = (parameter, _) -> {
         mutatorCalled = true;
         return parameter;
     };
-    protected ObjIntConsumer<ITEM> resultMutator = (item, index) -> {
+
+    protected ObjIntConsumer<ITEM> resultMutator = (_, _) -> {
     };
 
     protected ModifiableTestDataCreator(int count) {
         super(count);
     }
 
-    public CREATOR modifyParameter(@NonNull BiFunction<PARAMETER, Integer, PARAMETER> parameterMutator) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public CREATOR modifyParameter(BiFunction<PARAMETER, Integer, PARAMETER> parameterMutator) {
         this.parameterMutator = (parameter, index) -> {
             mutatorCalled = true;
             return parameterMutator.apply(parameter, index);
@@ -38,7 +42,8 @@ public CREATOR modifyParameter(@NonNull BiFunction<PARAMETER, Integer, PARAMETER
         return (CREATOR) this;
     }
 
-    public CREATOR modifyParameter(@NonNull UnaryOperator<PARAMETER> parameterMutator) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public CREATOR modifyParameter(UnaryOperator<PARAMETER> parameterMutator) {
         this.parameterMutator = (parameter, index) -> {
             mutatorCalled = true;
             return parameterMutator.apply(parameter);
@@ -47,12 +52,14 @@ public CREATOR modifyParameter(@NonNull UnaryOperator<PARAMETER> parameterMutato
         return (CREATOR) this;
     }
 
-    public CREATOR modifyResult(@NonNull ObjIntConsumer<ITEM> resultMutator) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public CREATOR modifyResult(ObjIntConsumer<ITEM> resultMutator) {
         this.resultMutator = resultMutator;
         return (CREATOR) this;
     }
 
-    public CREATOR modifyResult(@NonNull Consumer<ITEM> resultMutator) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public CREATOR modifyResult(Consumer<ITEM> resultMutator) {
         this.resultMutator = (item, index) -> resultMutator.accept(item);
         return (CREATOR) this;
     }
@@ -79,5 +86,5 @@ protected List<ITEM> create() {
         return result;
     }
 
-    protected abstract ITEM saveMutation(@NonNull ITEM item);
+    protected abstract ITEM saveMutation(ITEM item);
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/testdata/base/TestDataCreator.java b/src/main/java/it/aboutbits/springboot/testing/testdata/base/TestDataCreator.java
index e9ef674..c5a810a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/testdata/base/TestDataCreator.java
+++ b/src/main/java/it/aboutbits/springboot/testing/testdata/base/TestDataCreator.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.testdata.base;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.ArrayList;
 import java.util.Comparator;
@@ -9,7 +9,10 @@
 import java.util.Set;
 import java.util.function.Function;
 
+@SuppressWarnings("java:S119")
+@NullMarked
 public abstract class TestDataCreator<ITEM> {
+    @SuppressWarnings("unused")
     protected static final FakerExtended FAKER = new FakerExtended();
 
     protected final int numberOfItems;
@@ -18,20 +21,24 @@ protected TestDataCreator(int numberOfItems) {
         this.numberOfItems = numberOfItems;
     }
 
+    @SuppressWarnings("unused")
     public void commit() {
         create();
     }
 
+    @SuppressWarnings("unused")
     public ITEM returnFirst() {
         return create().getFirst();
     }
 
+    @SuppressWarnings("unused")
     public List<ITEM> returnAll() {
         return create();
     }
 
     @SafeVarargs
-    public final List<ITEM> returnSorted(@NonNull Comparator<ITEM>... comparators) {
+    @SuppressWarnings("unused")
+    public final List<ITEM> returnSorted(Comparator<ITEM>... comparators) {
         if (comparators.length == 0) {
             throw new IllegalArgumentException("At least one comparator must be provided");
         }
@@ -45,8 +52,8 @@ public final List<ITEM> returnSorted(@NonNull Comparator<ITEM>... comparators) {
     }
 
     @SafeVarargs
-    @SuppressWarnings("unchecked")
-    public final <U extends Comparable<? super U>> List<ITEM> returnSorted(@NonNull Function<ITEM, ? extends Comparable<?>>... comparators) {
+    @SuppressWarnings({"unchecked", "unused"})
+    public final <U extends Comparable<? super U>> List<ITEM> returnSorted(Function<ITEM, ? extends Comparable<?>>... comparators) {
         if (comparators.length == 0) {
             throw new IllegalArgumentException("At least one comparator must be provided");
         }
@@ -59,6 +66,7 @@ public final <U extends Comparable<? super U>> List<ITEM> returnSorted(@NonNull
         return returnAll().stream().sorted(combinedComparator).toList();
     }
 
+    @SuppressWarnings("unused")
     public Set<ITEM> returnSet() {
         return new HashSet<>(create());
     }
@@ -76,5 +84,4 @@ protected List<ITEM> create() {
     }
 
     protected abstract ITEM create(int index);
-
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseRuleBuilder.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseRuleBuilder.java
index 2e2f831..adc4fc4 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseRuleBuilder.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseRuleBuilder.java
@@ -18,15 +18,16 @@
 import it.aboutbits.springboot.testing.validation.rule.ValidBeanRule;
 import lombok.AccessLevel;
 import lombok.Getter;
-import lombok.NonNull;
-import lombok.RequiredArgsConstructor;
 import lombok.Setter;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.Consumer;
 
-@RequiredArgsConstructor
+@NullMarked
 public abstract class BaseRuleBuilder<R extends BaseRuleBuilder<R>> implements
         ValidationRulesData,
         BetweenRule<R>,
@@ -52,18 +53,20 @@ public abstract class BaseRuleBuilder<R extends BaseRuleBuilder<R>> implements
     private final List<CustomValidationFunction> validationFunctions = new ArrayList<>();
 
     @Setter(AccessLevel.PACKAGE)
+    @Nullable
     private Runnable triggerValidation;
 
     @Override
-    public void addRule(@NonNull Rule rule) {
+    public void addRule(Rule rule) {
         rules.add(rule);
     }
 
     @Override
-    public void addValidationFunction(@NonNull CustomValidationFunction function) {
+    public void addValidationFunction(CustomValidationFunction function) {
         validationFunctions.add(function);
     }
 
+    @SuppressWarnings("unchecked")
     public <T extends BaseRuleBuilder<T>> T withAdditionalRules(Consumer<T> registrar) {
         var self = (T) this;
         registrar.accept(self);
@@ -71,6 +74,7 @@ public <T extends BaseRuleBuilder<T>> T withAdditionalRules(Consumer<T> registra
     }
 
     public void isCompliant() {
+        Objects.requireNonNull(triggerValidation);
         triggerValidation.run();
     }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseValidationAssert.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseValidationAssert.java
index a573230..c81ccae 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseValidationAssert.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/BaseValidationAssert.java
@@ -4,10 +4,11 @@
 import jakarta.validation.Valid;
 import lombok.AccessLevel;
 import lombok.Getter;
-import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 import lombok.Setter;
 import org.apache.logging.log4j.util.TriConsumer;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.springframework.validation.annotation.Validated;
 
 import java.util.Arrays;
@@ -19,6 +20,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 @RequiredArgsConstructor(access = AccessLevel.PROTECTED)
+@NullMarked
 public abstract class BaseValidationAssert<R extends BaseRuleBuilder<?>> {
     @Getter(AccessLevel.PROTECTED)
     private final R ruleBuilder;
@@ -30,9 +32,11 @@ public abstract class BaseValidationAssert<R extends BaseRuleBuilder<?>> {
             )
     );
 
+    @Nullable
     private Object parameterUnderTest;
 
     @Setter(AccessLevel.PRIVATE)
+    @Nullable
     private Consumer<?> functionToCallWithParameter = null;
 
     /**
@@ -45,7 +49,7 @@ public static void registerNonBeanType(Class<?> type) {
         NON_BEAN_TYPES.add(type);
     }
 
-    public <P> CallBuilder<R, P> of(@NonNull P parameterUnderTest) {
+    public <P> CallBuilder<R, P> of(P parameterUnderTest) {
         this.parameterUnderTest = parameterUnderTest;
         ruleBuilder.setTriggerValidation(this::assertValidation);
         return new CallBuilder<>(this);
@@ -53,9 +57,9 @@ public <P> CallBuilder<R, P> of(@NonNull P parameterUnderTest) {
 
     @SuppressWarnings("unused")
     public AnnotationChecker calling(
-            @NonNull Class<?> classUnderTest,
-            @NonNull String methodName,
-            @NonNull Class<?>... methodParameterTypes
+            Class<?> classUnderTest,
+            String methodName,
+            Class<?>... methodParameterTypes
     ) {
         return new AnnotationChecker(classUnderTest, methodName, methodParameterTypes);
     }
@@ -93,7 +97,7 @@ public static final class CallBuilder<R extends BaseRuleBuilder<?>, P> {
         private final BaseValidationAssert<R> parent;
 
         @SuppressWarnings("unused")
-        public R calling(@NonNull Consumer<P> functionToCallWithParameter) {
+        public R calling(Consumer<P> functionToCallWithParameter) {
             parent.setFunctionToCallWithParameter(functionToCallWithParameter);
             return parent.ruleBuilder;
         }
@@ -105,8 +109,8 @@ public R usingBeanValidation() {
 
         @SuppressWarnings({"unused", "unchecked"})
         public <ID> R calling(
-                @NonNull BiConsumer<ID, P> functionToCallWithParameter,
-                @NonNull ID id
+                BiConsumer<ID, P> functionToCallWithParameter,
+                ID id
         ) {
             parent.setFunctionToCallWithParameter(
                     p -> functionToCallWithParameter.accept(id, (P) p)
@@ -116,9 +120,9 @@ public <ID> R calling(
 
         @SuppressWarnings({"unused", "unchecked"})
         public <A, B> R calling(
-                @NonNull TriConsumer<A, B, P> functionToCallWithParameter,
-                @NonNull A a,
-                @NonNull B b
+                TriConsumer<A, B, P> functionToCallWithParameter,
+                A a,
+                B b
         ) {
             parent.setFunctionToCallWithParameter(
                     p -> functionToCallWithParameter.accept(a, b, (P) p)
@@ -128,6 +132,9 @@ public <A, B> R calling(
     }
 
     private void assertValidation() {
+        if (parameterUnderTest == null) {
+            throw new IllegalStateException("Parameter under test not set.");
+        }
         new RuleValidator<>().assertValidation(
                 new RuleValidator.AssertionParameter<>(
                         parameterUnderTest,
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/CustomValidationFunction.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/CustomValidationFunction.java
index d268d3b..1f8ab44 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/CustomValidationFunction.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/CustomValidationFunction.java
@@ -1,7 +1,10 @@
 package it.aboutbits.springboot.testing.validation.core;
 
+import org.jspecify.annotations.NullMarked;
+
 import java.util.function.Function;
 
+@NullMarked
 public interface CustomValidationFunction extends Function<Object, CustomValidationFunction.Result> {
     record Result(boolean valid, String message) {
     }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/Rule.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/Rule.java
index 48cdbdf..ccdf75a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/Rule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/Rule.java
@@ -3,7 +3,9 @@
 import it.aboutbits.springboot.testing.validation.source.InertValueSource;
 import lombok.AccessLevel;
 import lombok.Getter;
+import org.jspecify.annotations.NullMarked;
 
+@NullMarked
 public final class Rule {
     @Getter(AccessLevel.PACKAGE)
     private final String property;
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidationException.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidationException.java
index 3260b67..c69cef1 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidationException.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidationException.java
@@ -1,5 +1,8 @@
 package it.aboutbits.springboot.testing.validation.core;
 
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
 class RuleValidationException extends RuntimeException {
     RuleValidationException(String message) {
         super(message);
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
index e77a595..98e9228 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
@@ -6,9 +6,9 @@
 import jakarta.validation.Validation;
 import jakarta.validation.Validator;
 import jakarta.validation.ValidatorFactory;
-import lombok.NonNull;
 import lombok.SneakyThrows;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
@@ -41,19 +41,16 @@
  * @nonBeanTypes This is a whitelist that holds classes that don't implicitly require @Valid. We assume that @Valid is required
  * for all substructures.
  */
+@NullMarked
 final class RuleValidator<P> {
     private static final ValidatorFactory VALIDATOR_FACTORY = Validation.buildDefaultValidatorFactory();
 
     record AssertionParameter<P>(
-            @NonNull
             P parameterUnderTest,
             @Nullable
             Consumer<?> functionToCallWithParameter,
-            @NonNull
             List<Rule> rules,
-            @NonNull
             List<CustomValidationFunction> functions,
-            @NonNull
             Set<Class<?>> nonBeanTypes
     ) {
     }
@@ -117,6 +114,7 @@ private static HashSet<String> getPropertyNamesThatHaveRules(List<Rule> rules) {
 
     private static <P> void assertThatSuppliedParameterIsValid(
             P parameterUnderTest,
+            @Nullable
             Consumer<P> functionToCallWithParameter,
             Validator validator
     ) {
@@ -132,7 +130,7 @@ private static <P> void assertThatSuppliedParameterIsValid(
                                 violatingFieldMessages.collect(Collectors.joining(" | "))
                         )
                         .isFalse();
-            } catch (Exception ignored) {
+            } catch (Exception _) {
                 // ignore any other exceptions
             }
         } else {
@@ -164,6 +162,7 @@ private static Stream<String> getViolatingFieldMessages(Set<ConstraintViolation<
     private static <P> void assertThatValidationIsCompliantForEachProperty(
             List<Rule> rules,
             P parameterUnderTest,
+            @Nullable
             Consumer<P> functionToCallWithParameter,
             Validator validator
     ) {
@@ -271,7 +270,6 @@ private static <P> void checkIfNestedValidationIsEnabledForNestedRecords(
         }
     }
 
-    @NonNull
     @SneakyThrows(ReflectiveOperationException.class)
     private static <P> Stream<?> getValues(Rule rule, P parameterUnderTest) {
         var source = (ValueSource) rule.getValueSource().getDeclaredConstructors()[0].newInstance();
@@ -279,7 +277,7 @@ private static <P> Stream<?> getValues(Rule rule, P parameterUnderTest) {
         return source.values(getPropertyType(rule.getProperty(), parameterUnderTest), rule.getArgs());
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "java:S3011"})
     private static <T> T createCopyWithAlteredProperty(T original, String property, Object alteredValue) {
         try {
             // Get the class of the original object
@@ -334,6 +332,7 @@ private static <T> T createCopyWithAlteredProperty(T original, String property,
         }
     }
 
+    @SuppressWarnings("java:S3011")
     private static <T> T createCopyWithAlteredValues(
             Class<T> clazz,
             Class<?>[] parameterTypes,
@@ -348,7 +347,7 @@ private static <T> T createCopyWithAlteredValues(
 
             // Create a copy with the altered property value
             instance = constructor.newInstance(newPropertyValues);
-        } catch (NoSuchMethodException e) {
+        } catch (NoSuchMethodException _) {
             // Get the no args constructor
             var constructor = clazz.getDeclaredConstructor();
             constructor.setAccessible(true);
@@ -393,11 +392,11 @@ private static <T> boolean hasValidAnnotation(String propertyName, T object) {
     private static boolean hasNullableAnnotation(String propertyName, Object object) {
         var field = getFieldOrFail(propertyName, object);
 
-        return field.getAnnotation(org.springframework.lang.Nullable.class) != null
-                || field.getAnnotation(jakarta.annotation.Nullable.class) != null;
+        return field.getAnnotatedType().isAnnotationPresent(org.jspecify.annotations.Nullable.class)
+                || field.isAnnotationPresent(jakarta.annotation.Nullable.class)
+                || field.isAnnotationPresent(org.springframework.lang.Nullable.class);
     }
 
-    @NonNull
     private static Field getFieldOrFail(String propertyName, Object object) {
         var clazz = object.getClass();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/ValidationRulesData.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/ValidationRulesData.java
index 8c43829..01f8e7e 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/ValidationRulesData.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/ValidationRulesData.java
@@ -1,9 +1,11 @@
 package it.aboutbits.springboot.testing.validation.core;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
+@SuppressWarnings("unused")
+@NullMarked
 public interface ValidationRulesData {
-    void addRule(@NonNull Rule rule);
+    void addRule(Rule rule);
 
-    void addValidationFunction(@NonNull CustomValidationFunction function);
+    void addValidationFunction(CustomValidationFunction function);
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/ValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/ValueSource.java
index 290191f..e9e7794 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/ValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/ValueSource.java
@@ -1,7 +1,10 @@
 package it.aboutbits.springboot.testing.validation.core;
 
+import org.jspecify.annotations.NullMarked;
+
 import java.util.stream.Stream;
 
+@NullMarked
 public interface ValueSource {
     <T> Stream<T> values(Class<T> propertyClass, Object... args);
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/BetweenRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/BetweenRule.java
index 285cfe3..ce16810 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/BetweenRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/BetweenRule.java
@@ -5,11 +5,12 @@
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BiggerThanValueSource;
 import it.aboutbits.springboot.testing.validation.source.LessThanValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface BetweenRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V between(@NonNull String property, long min, long max) {
+    default V between(String property, long min, long max) {
         addRule(
                 new Rule(property, BiggerThanValueSource.class, max)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/FutureRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/FutureRule.java
index 7da2a2d..aef2e22 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/FutureRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/FutureRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.PastValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface FutureRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V future(@NonNull String property) {
+    default V future(String property) {
         addRule(
                 new Rule(property, PastValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/MaxRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/MaxRule.java
index 4858067..1ffae34 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/MaxRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/MaxRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BiggerThanValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface MaxRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V max(@NonNull String property, long max) {
+    default V max(String property, long max) {
         addRule(
                 new Rule(property, BiggerThanValueSource.class, max)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/MinRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/MinRule.java
index 5484f08..57f0a33 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/MinRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/MinRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.LessThanValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface MinRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V min(@NonNull String property, long min) {
+    default V min(String property, long min) {
         addRule(
                 new Rule(property, LessThanValueSource.class, min)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeOrZeroRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeOrZeroRule.java
index 4852867..e1af433 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeOrZeroRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeOrZeroRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BiggerThanValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NegativeOrZeroRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V negativeOrZero(@NonNull String property) {
+    default V negativeOrZero(String property) {
         addRule(
                 new Rule(property, BiggerThanValueSource.class, 0L)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeRule.java
index e420f2e..888834f 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NegativeRule.java
@@ -5,11 +5,12 @@
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BiggerThanValueSource;
 import it.aboutbits.springboot.testing.validation.source.ZeroValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NegativeRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V negative(@NonNull String property) {
+    default V negative(String property) {
         addRule(
                 new Rule(property, BiggerThanValueSource.class, 0L)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
index 8914566..6d020c6 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
@@ -5,11 +5,12 @@
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BlankValueSource;
 import it.aboutbits.springboot.testing.validation.source.NullValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NotBlankRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V notBlank(@NonNull String property) {
+    default V notBlank(String property) {
         addRule(
                 new Rule(property, BlankValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
index b95bd7a..612a704 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
@@ -5,11 +5,12 @@
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.EmptyValueSource;
 import it.aboutbits.springboot.testing.validation.source.NullValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NotEmptyRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V notEmpty(@NonNull String property) {
+    default V notEmpty(String property) {
         addRule(
                 new Rule(property, EmptyValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotNullRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotNullRule.java
index 5346ae9..d78b1df 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotNullRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotNullRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.NullValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NotNullRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V notNull(@NonNull String property) {
+    default V notNull(String property) {
         addRule(
                 new Rule(property, NullValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotValidatedRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotValidatedRule.java
index 3e00e20..45fb5d5 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotValidatedRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotValidatedRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.InertValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NotValidatedRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V notValidated(@NonNull String property) {
+    default V notValidated(String property) {
         addRule(
                 new Rule(property, InertValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NullableRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NullableRule.java
index 69a33c4..776db9e 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NullableRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NullableRule.java
@@ -3,11 +3,12 @@
 import it.aboutbits.springboot.testing.validation.core.BaseRuleBuilder;
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface NullableRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V nullable(@NonNull String property) {
+    default V nullable(String property) {
         addRule(
                 Rule.nullableAnnotated(property)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PastRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PastRule.java
index b61dd7d..a0c965d 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PastRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PastRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.FutureValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface PastRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V past(@NonNull String property) {
+    default V past(String property) {
         addRule(
                 new Rule(property, FutureValueSource.class)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveOrZeroRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveOrZeroRule.java
index ba9a3fe..f590a7a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveOrZeroRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveOrZeroRule.java
@@ -4,11 +4,12 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.LessThanValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface PositiveOrZeroRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V positiveOrZero(@NonNull String property) {
+    default V positiveOrZero(String property) {
         addRule(
                 new Rule(property, LessThanValueSource.class, 0L)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveRule.java
index bf9b25b..abca7e6 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/PositiveRule.java
@@ -5,11 +5,12 @@
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.LessThanValueSource;
 import it.aboutbits.springboot.testing.validation.source.ZeroValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface PositiveRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V positive(@NonNull String property) {
+    default V positive(String property) {
         addRule(
                 new Rule(property, LessThanValueSource.class, 0L)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/SizeRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/SizeRule.java
index 6f7130b..4fc5a11 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/SizeRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/SizeRule.java
@@ -6,12 +6,13 @@
 import it.aboutbits.springboot.testing.validation.source.SizeGreaterThanValueSource;
 import it.aboutbits.springboot.testing.validation.source.SizeLessThanValueSource;
 import lombok.AccessLevel;
-import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface SizeRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default Builder<V> size(@NonNull String property) {
+    default Builder<V> size(String property) {
         return new Builder<>((V) this, property);
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/ValidBeanRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/ValidBeanRule.java
index 7c3e7ae..a832898 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/ValidBeanRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/ValidBeanRule.java
@@ -3,11 +3,12 @@
 import it.aboutbits.springboot.testing.validation.core.BaseRuleBuilder;
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 @SuppressWarnings("unchecked")
+@NullMarked
 public interface ValidBeanRule<V extends BaseRuleBuilder<?>> extends ValidationRulesData {
-    default V validBean(@NonNull String property) {
+    default V validBean(String property) {
         addRule(
                 Rule.validAnnotated(property)
         );
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/BiggerThanValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/BiggerThanValueSource.java
index 62f5667..c025aba 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/BiggerThanValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/BiggerThanValueSource.java
@@ -2,7 +2,7 @@
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
 import it.aboutbits.springboot.toolbox.type.ScaledBigDecimal;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -12,6 +12,7 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class BiggerThanValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
     private static final Random RANDOM = new Random();
@@ -56,7 +57,6 @@ public <T> Stream<T> values(Class<T> propertyClass, Object... args) {
         throw new IllegalArgumentException("Property class not supported!");
     }
 
-    @NonNull
     private static Stream<Byte> getByteStream(Object[] args) {
         var minValue = (byte) (Long.valueOf((long) args[0]).byteValue() + 1);
         var maxValue = Byte.MAX_VALUE;
@@ -68,7 +68,6 @@ private static Stream<Byte> getByteStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Short> getShortStream(Object[] args) {
         var minValue = (short) (Long.valueOf((long) args[0]).shortValue() + 1);
         var maxValue = Short.MAX_VALUE;
@@ -80,7 +79,6 @@ private static Stream<Short> getShortStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Integer> getIntegerStream(Object[] args) {
         var minValue = Long.valueOf((long) args[0]).intValue() + 1;
         var maxValue = Integer.MAX_VALUE;
@@ -91,7 +89,6 @@ private static Stream<Integer> getIntegerStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Long> getLongStream(Object[] args) {
         var minValue = (long) args[0] + 1;
         var maxValue = Long.MAX_VALUE;
@@ -102,7 +99,6 @@ private static Stream<Long> getLongStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Float> getFloatStream(Object[] args) {
         var minValue = Long.valueOf((long) args[0]).floatValue() + 0.1f;
         var maxValue = Float.MAX_VALUE;
@@ -115,7 +111,6 @@ private static Stream<Float> getFloatStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Double> getDoubleStream(Object[] args) {
         var minValue = Long.valueOf((long) args[0]).doubleValue() + 0.1d;
         var maxValue = Double.MAX_VALUE;
@@ -126,7 +121,6 @@ private static Stream<Double> getDoubleStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<BigInteger> getBigIntegerStream(Object[] args) {
         var minValue = (long) args[0] + 1;
         var maxValue = Long.MAX_VALUE;
@@ -139,9 +133,8 @@ private static Stream<BigInteger> getBigIntegerStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<BigDecimal> getBigDecimalStream(Object[] args) {
-        var minValue = Long.valueOf((long) args[0]).doubleValue() + 0.1d;
+        var minValue = (long) args[0] + 0.1d;
         var maxValue = Double.MAX_VALUE;
 
         return Stream.concat(
@@ -152,9 +145,8 @@ private static Stream<BigDecimal> getBigDecimalStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<ScaledBigDecimal> getScaledBigDecimalStream(Object[] args) {
-        var minValue = Long.valueOf((long) args[0]).doubleValue() + 0.1d;
+        var minValue = (long) args[0] + 0.1d;
         var maxValue = Double.MAX_VALUE;
 
         return Stream.concat(
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/BlankValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/BlankValueSource.java
index c478ebd..8e3b96d 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/BlankValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/BlankValueSource.java
@@ -1,12 +1,14 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class BlankValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/EmptyValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/EmptyValueSource.java
index cb8539a..1567f0c 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/EmptyValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/EmptyValueSource.java
@@ -1,6 +1,7 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -11,6 +12,7 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class EmptyValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/FutureValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/FutureValueSource.java
index d1d5db1..82d5a72 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/FutureValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/FutureValueSource.java
@@ -1,6 +1,7 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.time.Instant;
 import java.time.LocalDate;
@@ -18,6 +19,7 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class FutureValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/InertValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/InertValueSource.java
index 7e895b6..f833467 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/InertValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/InertValueSource.java
@@ -1,9 +1,11 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.stream.Stream;
 
+@NullMarked
 public class InertValueSource implements ValueSource {
     @Override
     public <T> Stream<T> values(Class<T> propertyClass, Object... args) {
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/LessThanValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/LessThanValueSource.java
index 6f68e89..798f542 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/LessThanValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/LessThanValueSource.java
@@ -2,7 +2,7 @@
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
 import it.aboutbits.springboot.toolbox.type.ScaledBigDecimal;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -13,6 +13,7 @@
 import java.util.stream.Stream;
 
 // For floating point values: The negative max value is the minimum, MIN_VALUE is the smallest positive
+@NullMarked
 public class LessThanValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
     private static final Random RANDOM = new Random();
@@ -57,7 +58,6 @@ public <T> Stream<T> values(Class<T> propertyClass, Object... args) {
         throw new IllegalArgumentException("Property class not supported!");
     }
 
-    @NonNull
     private static Stream<Byte> getByteStream(Object[] args) {
         var minValue = Byte.MIN_VALUE;
         var maxValue = (byte) (Long.valueOf((long) args[0]).byteValue() - 1);
@@ -69,7 +69,6 @@ private static Stream<Byte> getByteStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Short> getShortStream(Object[] args) {
         var minValue = Short.MIN_VALUE;
         var maxValue = (short) (Long.valueOf((long) args[0]).shortValue() - 1);
@@ -81,7 +80,6 @@ private static Stream<Short> getShortStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Integer> getIntegerStream(Object[] args) {
         var minValue = Integer.MIN_VALUE;
         var maxValue = Long.valueOf((long) args[0]).intValue() - 1;
@@ -92,7 +90,6 @@ private static Stream<Integer> getIntegerStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Long> getLongStream(Object[] args) {
         var minValue = Long.MIN_VALUE;
         var maxValue = (long) args[0] - 1;
@@ -103,7 +100,6 @@ private static Stream<Long> getLongStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Float> getFloatStream(Object[] args) {
         var minValue = Float.MAX_VALUE * -1;
         var maxValue = Long.valueOf((long) args[0]).floatValue() - 0.1f;
@@ -116,7 +112,6 @@ private static Stream<Float> getFloatStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<Double> getDoubleStream(Object[] args) {
         var minValue = Double.MAX_VALUE * -1;
         var maxValue = Long.valueOf((long) args[0]).doubleValue() - 0.1d;
@@ -127,7 +122,6 @@ private static Stream<Double> getDoubleStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<BigInteger> getBigIntegerStream(Object[] args) {
         var minValue = Long.MIN_VALUE;
         var maxValue = (long) args[0] - 1;
@@ -140,7 +134,6 @@ private static Stream<BigInteger> getBigIntegerStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<BigDecimal> getBigDecimalStream(Object[] args) {
         var minValue = Double.MAX_VALUE * -1;
         var maxValue = Long.valueOf((long) args[0]).doubleValue() - 0.1d;
@@ -153,7 +146,6 @@ private static Stream<BigDecimal> getBigDecimalStream(Object[] args) {
         );
     }
 
-    @NonNull
     private static Stream<ScaledBigDecimal> getScaledBigDecimalStream(Object[] args) {
         var minValue = Double.MAX_VALUE * -1;
         var maxValue = Long.valueOf((long) args[0]).doubleValue() - 0.1d;
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/NullValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/NullValueSource.java
index 3bb9c5c..25cb35a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/NullValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/NullValueSource.java
@@ -1,12 +1,14 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class NullValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/PastValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/PastValueSource.java
index d63ba46..2642f83 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/PastValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/PastValueSource.java
@@ -1,6 +1,7 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
+import org.jspecify.annotations.NullMarked;
 
 import java.time.Instant;
 import java.time.LocalDate;
@@ -18,6 +19,7 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class PastValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeGreaterThanValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeGreaterThanValueSource.java
index 0b1c982..001a4ae 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeGreaterThanValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeGreaterThanValueSource.java
@@ -1,7 +1,7 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.lang.reflect.Array;
 import java.util.ArrayList;
@@ -22,6 +22,7 @@
 import java.util.function.LongFunction;
 import java.util.stream.Stream;
 
+@NullMarked
 public class SizeGreaterThanValueSource implements ValueSource {
     private static final Map<Class<?>, LongFunction<Stream<?>>> TYPE_SOURCES = new HashMap<>();
     private static final Random RANDOM = new Random();
@@ -75,17 +76,14 @@ private static Stream<?> arrayFunction(Class<?> arrayClass, long value) {
                         Math.toIntExact(size),
                         arrayClass
                 ));
-
     }
 
-    @NonNull
     private static Stream<String> getStringStream(long value) {
         return getTestSizes(value)
                 .stream()
                 .map(size -> generateRandomString(Math.toIntExact(size)));
     }
 
-    @NonNull
     private static Stream<Collection<?>> getHashSetStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -95,7 +93,6 @@ private static Stream<Collection<?>> getHashSetStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Collection<?>> getLinkedHashSetStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -105,7 +102,6 @@ private static Stream<Collection<?>> getLinkedHashSetStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Collection<?>> getTreeSetStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -115,7 +111,6 @@ private static Stream<Collection<?>> getTreeSetStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Collection<?>> getArrayListStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -125,7 +120,6 @@ private static Stream<Collection<?>> getArrayListStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Collection<?>> getLinkedListStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -135,7 +129,6 @@ private static Stream<Collection<?>> getLinkedListStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getHashMapStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -145,7 +138,6 @@ private static Stream<Collection<?>> getLinkedListStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getLinkedHashMapStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -155,7 +147,6 @@ private static Stream<Collection<?>> getLinkedListStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getTreeMapStream(long value) {
         return getTestSizes(value)
                 .stream()
@@ -165,7 +156,6 @@ private static Stream<Collection<?>> getLinkedListStream(long value) {
                 ));
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getConcurrentHashMapStream(long value) {
         return getTestSizes(value)
                 .stream()
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeLessThanValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeLessThanValueSource.java
index 6c69893..36c96fc 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeLessThanValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/SizeLessThanValueSource.java
@@ -1,7 +1,7 @@
 package it.aboutbits.springboot.testing.validation.source;
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 
 import java.lang.reflect.Array;
 import java.util.ArrayList;
@@ -22,6 +22,7 @@
 import java.util.function.LongFunction;
 import java.util.stream.Stream;
 
+@NullMarked
 public class SizeLessThanValueSource implements ValueSource {
     private static final Map<Class<?>, LongFunction<Stream<?>>> TYPE_SOURCES = new HashMap<>();
     private static final Random RANDOM = new Random();
@@ -86,7 +87,6 @@ private static Stream<?> arrayFunction(Class<?> arrayClass, long value) {
         );
     }
 
-    @NonNull
     private static Stream<String> getStringStream(long value) {
         return Stream.concat(
                 Stream.of(""),
@@ -95,7 +95,6 @@ private static Stream<String> getStringStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Collection<?>> getArrayListStream(long value) {
         return Stream.concat(
                 Stream.of(new ArrayList<>()),
@@ -107,7 +106,6 @@ private static Stream<Collection<?>> getArrayListStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Collection<?>> getLinkedListStream(long value) {
         return Stream.concat(
                 Stream.of(new LinkedList<>()),
@@ -119,7 +117,6 @@ private static Stream<Collection<?>> getLinkedListStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Collection<?>> getHashSetStream(long value) {
         return Stream.concat(
                 Stream.of(new HashSet<>()),
@@ -131,7 +128,6 @@ private static Stream<Collection<?>> getHashSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Collection<?>> getLinkedHashSetStream(long value) {
         return Stream.concat(
                 Stream.of(new LinkedHashSet<>()),
@@ -143,7 +139,6 @@ private static Stream<Collection<?>> getLinkedHashSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Collection<?>> getTreeSetStream(long value) {
         return Stream.concat(
                 Stream.of(new TreeSet<>()),
@@ -155,7 +150,6 @@ private static Stream<Collection<?>> getTreeSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getHashMapStream(long value) {
         return Stream.concat(
                 Stream.of(new HashMap<>()),
@@ -167,7 +161,6 @@ private static Stream<Collection<?>> getTreeSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getLinkedHashMapStream(long value) {
         return Stream.concat(
                 Stream.of(new LinkedHashMap<>()),
@@ -179,7 +172,6 @@ private static Stream<Collection<?>> getTreeSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getTreeMapStream(long value) {
         return Stream.concat(
                 Stream.of(new TreeMap<>()),
@@ -191,7 +183,6 @@ private static Stream<Collection<?>> getTreeSetStream(long value) {
         );
     }
 
-    @NonNull
     private static Stream<Map<?, ?>> getConcurrentHashMapStream(long value) {
         return Stream.concat(
                 Stream.of(new ConcurrentHashMap<>()),
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/source/ZeroValueSource.java b/src/main/java/it/aboutbits/springboot/testing/validation/source/ZeroValueSource.java
index fc15b06..016cbf4 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/source/ZeroValueSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/source/ZeroValueSource.java
@@ -2,6 +2,7 @@
 
 import it.aboutbits.springboot.testing.validation.core.ValueSource;
 import it.aboutbits.springboot.toolbox.type.ScaledBigDecimal;
+import org.jspecify.annotations.NullMarked;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -10,6 +11,7 @@
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+@NullMarked
 public class ZeroValueSource implements ValueSource {
     private static final Map<Class<?>, Function<Object[], Stream<?>>> TYPE_SOURCES = new HashMap<>();
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/valuesource/BlankSource.java b/src/main/java/it/aboutbits/springboot/testing/valuesource/BlankSource.java
index 1ef3be6..45995d7 100644
--- a/src/main/java/it/aboutbits/springboot/testing/valuesource/BlankSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/valuesource/BlankSource.java
@@ -8,6 +8,7 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+@SuppressWarnings("unused")
 @Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
diff --git a/src/main/java/it/aboutbits/springboot/testing/valuesource/NullAndBlankSource.java b/src/main/java/it/aboutbits/springboot/testing/valuesource/NullAndBlankSource.java
index 7b400f0..7f3fb31 100644
--- a/src/main/java/it/aboutbits/springboot/testing/valuesource/NullAndBlankSource.java
+++ b/src/main/java/it/aboutbits/springboot/testing/valuesource/NullAndBlankSource.java
@@ -8,6 +8,7 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+@SuppressWarnings("unused")
 @Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Delete.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Delete.java
index 5547b07..160c2a2 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Delete.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Delete.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
@@ -8,18 +8,19 @@
 
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
+@NullMarked
 public class Delete extends Request<MockHttpServletRequestBuilder> {
     Delete(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, APPLICATION_JSON, pathVariables);
     }
 
     @Override
-    protected @NonNull MockHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.delete(url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Get.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Get.java
index 1a0d9d7..59b2d6b 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Get.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Get.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
@@ -8,18 +8,19 @@
 
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
+@NullMarked
 public class Get extends Request<MockHttpServletRequestBuilder> {
     Get(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, APPLICATION_JSON, pathVariables);
     }
 
     @Override
-    protected @NonNull MockHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.get(url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestClient.java b/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestClient.java
index 5300b98..a005c96 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestClient.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestClient.java
@@ -1,45 +1,46 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import tools.jackson.databind.json.JsonMapper;
 
 @RequiredArgsConstructor
+@NullMarked
 public class HttpTestClient {
     private final MockMvc mockMvc;
     private final JsonMapper jsonMapper;
 
-    public Request<MockHttpServletRequestBuilder> get(@NonNull String url, Object... pathVariables) {
+    public Request<MockHttpServletRequestBuilder> get(String url, Object... pathVariables) {
         return new Get(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public Request<MockHttpServletRequestBuilder> put(@NonNull String url, Object... pathVariables) {
+    public Request<MockHttpServletRequestBuilder> put(String url, Object... pathVariables) {
         return new Put(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public MultipartRequest putMultipart(@NonNull String url, Object... pathVariables) {
+    public MultipartRequest putMultipart(String url, Object... pathVariables) {
         return new PutMultipart(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public Request<MockHttpServletRequestBuilder> post(@NonNull String url, Object... pathVariables) {
+    public Request<MockHttpServletRequestBuilder> post(String url, Object... pathVariables) {
         return new Post(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public MultipartRequest postMultipart(@NonNull String url, Object... pathVariables) {
+    public MultipartRequest postMultipart(String url, Object... pathVariables) {
         return new PostMultipart(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public Request<MockHttpServletRequestBuilder> patch(@NonNull String url, Object... pathVariables) {
+    public Request<MockHttpServletRequestBuilder> patch(String url, Object... pathVariables) {
         return new Patch(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public MultipartRequest patchMultipart(@NonNull String url, Object... pathVariables) {
+    public MultipartRequest patchMultipart(String url, Object... pathVariables) {
         return new PatchMultipart(mockMvc, jsonMapper, url, pathVariables);
     }
 
-    public Request<MockHttpServletRequestBuilder> delete(@NonNull String url, Object... pathVariables) {
+    public Request<MockHttpServletRequestBuilder> delete(String url, Object... pathVariables) {
         return new Delete(mockMvc, jsonMapper, url, pathVariables);
     }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestSecurity.java b/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestSecurity.java
index f6c4147..3712bf3 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestSecurity.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/HttpTestSecurity.java
@@ -1,32 +1,36 @@
 package it.aboutbits.springboot.testing.web.request;
 
 import lombok.Getter;
-import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.mock.web.MockMultipartFile;
 
 import static it.aboutbits.springboot.testing.web.request.RequestSecurityAssert.assertThatRequest;
 
 @Getter
 @RequiredArgsConstructor
+@NullMarked
 public class HttpTestSecurity {
     private final HttpTestClient httpTestClient;
 
-    public void assertGetGranted(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertGetGranted(String url, Object... pathVariables) {
         var result = httpTestClient.get(url, pathVariables)
                 .returnRaw();
 
         assertThatRequest(result).wasGranted();
     }
 
-    public void assertGetDenied(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertGetDenied(String url, Object... pathVariables) {
         var result = httpTestClient.get(url, pathVariables)
                 .returnRaw();
 
         assertThatRequest(result).wasDenied();
     }
 
-    public void assertPostGranted(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPostGranted(String url, Object... pathVariables) {
         var result = httpTestClient.post(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -34,7 +38,8 @@ public void assertPostGranted(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasGranted();
     }
 
-    public void assertPostDenied(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPostDenied(String url, Object... pathVariables) {
         var result = httpTestClient.post(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -42,9 +47,10 @@ public void assertPostDenied(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasDenied();
     }
 
+    @SuppressWarnings("unused")
     public void assertPostMultipartGranted(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.postMultipart(url, pathVariables)
@@ -54,9 +60,10 @@ public void assertPostMultipartGranted(
         assertThatRequest(result).wasGranted();
     }
 
+    @SuppressWarnings("unused")
     public void assertPostMultipartDenied(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.postMultipart(url, pathVariables)
@@ -66,7 +73,8 @@ public void assertPostMultipartDenied(
         assertThatRequest(result).wasDenied();
     }
 
-    public void assertPutGranted(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPutGranted(String url, Object... pathVariables) {
         var result = httpTestClient.put(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -74,7 +82,8 @@ public void assertPutGranted(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasGranted();
     }
 
-    public void assertPutDenied(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPutDenied(String url, Object... pathVariables) {
         var result = httpTestClient.put(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -82,9 +91,10 @@ public void assertPutDenied(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasDenied();
     }
 
+    @SuppressWarnings("unused")
     public void assertPutMultipartGranted(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.putMultipart(url, pathVariables)
@@ -94,9 +104,10 @@ public void assertPutMultipartGranted(
         assertThatRequest(result).wasGranted();
     }
 
+    @SuppressWarnings("unused")
     public void assertPutMultipartDenied(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.putMultipart(url, pathVariables)
@@ -106,7 +117,8 @@ public void assertPutMultipartDenied(
         assertThatRequest(result).wasDenied();
     }
 
-    public void assertPatchGranted(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPatchGranted(String url, Object... pathVariables) {
         var result = httpTestClient.patch(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -114,7 +126,8 @@ public void assertPatchGranted(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasGranted();
     }
 
-    public void assertPatchDenied(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertPatchDenied(String url, Object... pathVariables) {
         var result = httpTestClient.patch(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -122,9 +135,10 @@ public void assertPatchDenied(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasDenied();
     }
 
+    @SuppressWarnings("unused")
     public void assertPatchMultipartGranted(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.patchMultipart(url, pathVariables)
@@ -134,9 +148,10 @@ public void assertPatchMultipartGranted(
         assertThatRequest(result).wasGranted();
     }
 
+    @SuppressWarnings("unused")
     public void assertPatchMultipartDenied(
-            @NonNull String url,
-            @NonNull MockMultipartFile multipartFile,
+            String url,
+            MockMultipartFile multipartFile,
             Object... pathVariables
     ) {
         var result = httpTestClient.patchMultipart(url, pathVariables)
@@ -146,7 +161,8 @@ public void assertPatchMultipartDenied(
         assertThatRequest(result).wasDenied();
     }
 
-    public void assertDeleteGranted(@NonNull String url, Object... pathVariables) {
+    @SuppressWarnings("unused")
+    public void assertDeleteGranted(String url, Object... pathVariables) {
         var result = httpTestClient.delete(url, pathVariables)
                 .body("{}")
                 .returnRaw();
@@ -154,7 +170,7 @@ public void assertDeleteGranted(@NonNull String url, Object... pathVariables) {
         assertThatRequest(result).wasGranted();
     }
 
-    public void assertDeleteDenied(@NonNull String url, Object... pathVariables) {
+    public void assertDeleteDenied(String url, Object... pathVariables) {
         var result = httpTestClient.delete(url, pathVariables)
                 .body("{}")
                 .returnRaw();
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/MultipartRequest.java b/src/main/java/it/aboutbits/springboot/testing/web/request/MultipartRequest.java
index 0a4b2d9..76ac6af 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/MultipartRequest.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/MultipartRequest.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.mock.web.MockMultipartFile;
 import org.springframework.mock.web.MockPart;
 import org.springframework.test.web.servlet.MockMvc;
@@ -12,31 +12,34 @@
 
 import static org.springframework.http.MediaType.MULTIPART_FORM_DATA;
 
+@NullMarked
 public abstract class MultipartRequest extends Request<MockMultipartHttpServletRequestBuilder> {
     protected List<MockPart> parts = new ArrayList<>();
     protected List<MockMultipartFile> files = new ArrayList<>();
 
     MultipartRequest(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, MULTIPART_FORM_DATA, pathVariables);
     }
 
-    public MultipartRequest part(@NonNull MockPart part) {
+    @SuppressWarnings("unused")
+    public MultipartRequest part(MockPart part) {
         parts.add(part);
         return this;
     }
 
-    public MultipartRequest file(@NonNull MockMultipartFile file) {
+    @SuppressWarnings("unused")
+    public MultipartRequest file(MockMultipartFile file) {
         files.add(file);
         return this;
     }
 
     @Override
-    protected @NonNull MockMultipartHttpServletRequestBuilder prepareRequestBuilder() {
+    protected MockMultipartHttpServletRequestBuilder prepareRequestBuilder() {
         var requestBuilder = super.prepareRequestBuilder();
 
         for (var file : files) {
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Patch.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Patch.java
index 75c43b7..8e43e67 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Patch.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Patch.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
@@ -8,18 +8,19 @@
 
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
+@NullMarked
 public class Patch extends Request<MockHttpServletRequestBuilder> {
     Patch(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, APPLICATION_JSON, pathVariables);
     }
 
     @Override
-    protected @NonNull MockHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.patch(url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/PatchMultipart.java b/src/main/java/it/aboutbits/springboot/testing/web/request/PatchMultipart.java
index 9cc621d..2884440 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/PatchMultipart.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/PatchMultipart.java
@@ -1,24 +1,25 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.http.HttpMethod;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockMultipartHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
 import tools.jackson.databind.json.JsonMapper;
 
+@NullMarked
 public class PatchMultipart extends MultipartRequest {
     PatchMultipart(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, pathVariables);
     }
 
     @Override
-    protected @NonNull MockMultipartHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockMultipartHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.multipart(HttpMethod.PATCH, url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Post.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Post.java
index 404a8a7..206d550 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Post.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Post.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
@@ -8,18 +8,19 @@
 
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
+@NullMarked
 public class Post extends Request<MockHttpServletRequestBuilder> {
     Post(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, APPLICATION_JSON, pathVariables);
     }
 
     @Override
-    protected @NonNull MockHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.post(url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/PostMultipart.java b/src/main/java/it/aboutbits/springboot/testing/web/request/PostMultipart.java
index c65395f..077d883 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/PostMultipart.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/PostMultipart.java
@@ -1,24 +1,25 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.http.HttpMethod;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockMultipartHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
 import tools.jackson.databind.json.JsonMapper;
 
+@NullMarked
 public class PostMultipart extends MultipartRequest {
     PostMultipart(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, pathVariables);
     }
 
     @Override
-    protected @NonNull MockMultipartHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockMultipartHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.multipart(HttpMethod.POST, url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Put.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Put.java
index 78e3aae..f1085fc 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Put.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Put.java
@@ -1,6 +1,6 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
@@ -8,18 +8,19 @@
 
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
+@NullMarked
 public class Put extends Request<MockHttpServletRequestBuilder> {
     Put(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, APPLICATION_JSON, pathVariables);
     }
 
     @Override
-    protected @NonNull MockHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.put(url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/PutMultipart.java b/src/main/java/it/aboutbits/springboot/testing/web/request/PutMultipart.java
index 82fd1cc..38b036c 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/PutMultipart.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/PutMultipart.java
@@ -1,24 +1,25 @@
 package it.aboutbits.springboot.testing.web.request;
 
-import lombok.NonNull;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.http.HttpMethod;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockMultipartHttpServletRequestBuilder;
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
 import tools.jackson.databind.json.JsonMapper;
 
+@NullMarked
 public class PutMultipart extends MultipartRequest {
     PutMultipart(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper objectMapper,
-            @NonNull String url,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper objectMapper,
+            String url,
+            Object... pathVariables
     ) {
         super(mockMvc, objectMapper, url, pathVariables);
     }
 
     @Override
-    protected @NonNull MockMultipartHttpServletRequestBuilder getRequestBuilder(@NonNull UrlWithVariables url) {
+    protected MockMultipartHttpServletRequestBuilder getRequestBuilder(UrlWithVariables url) {
         return MockMvcRequestBuilders.multipart(HttpMethod.PUT, url.url(), url.pathVariables());
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/Request.java b/src/main/java/it/aboutbits/springboot/testing/web/request/Request.java
index ad52b2a..ef6f69a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/Request.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/Request.java
@@ -7,9 +7,10 @@
 import it.aboutbits.springboot.toolbox.web.response.PagedResponse;
 import it.aboutbits.springboot.toolbox.web.response.meta.Meta;
 import jakarta.servlet.http.Cookie;
-import lombok.NonNull;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.test.web.servlet.MockMvc;
@@ -28,7 +29,9 @@
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.csrf;
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.httpBasic;
 
+@SuppressWarnings("java:S1192")
 @Slf4j
+@NullMarked
 public abstract class Request<R extends AbstractMockHttpServletRequestBuilder<R>> {
     protected record UsernameAndPassword(String username, String password) {
     }
@@ -42,18 +45,20 @@ protected record UrlWithVariables(String url, Object... pathVariables) {
     protected final MediaType contentType;
 
     protected String body = "";
+    @Nullable
     protected HttpStatus status = null;
     protected Cookie[] cookies = new Cookie[0];
+    @Nullable
     protected UsernameAndPassword basicAuth = null;
     protected Map<String, String> parameters = new HashMap<>();
     protected Map<String, String[]> parametersArray = new HashMap<>();
 
     Request(
-            @NonNull MockMvc mockMvc,
-            @NonNull JsonMapper jsonMapper,
-            @NonNull String url,
-            @NonNull MediaType contentType,
-            @NonNull Object... pathVariables
+            MockMvc mockMvc,
+            JsonMapper jsonMapper,
+            String url,
+            MediaType contentType,
+            Object... pathVariables
     ) {
         this.jsonMapper = jsonMapper;
 
@@ -62,12 +67,14 @@ protected record UrlWithVariables(String url, Object... pathVariables) {
         this.contentType = contentType;
     }
 
-    public Request<R> cookies(@NonNull Cookie... cookies) {
+    @SuppressWarnings("unused")
+    public Request<R> cookies(Cookie... cookies) {
         this.cookies = cookies;
         return this;
     }
 
-    public Request<R> body(@NonNull Object body) {
+    @SuppressWarnings("unused")
+    public Request<R> body(Object body) {
         if (body instanceof String stringBody) {
             this.body = stringBody;
             return this;
@@ -77,17 +84,19 @@ public Request<R> body(@NonNull Object body) {
             this.body = jsonMapper.writeValueAsString(body);
         } catch (JacksonException e) {
             log.error("Failed to write body as JSON.", e);
-            throw new RuntimeException(e);
+            throw new RequestBodyException(e);
         }
         return this;
     }
 
-    public Request<R> param(@NonNull String name, Object value) {
+    @SuppressWarnings("unused")
+    public Request<R> param(String name, @Nullable Object value) {
         this.parameters.put(name, String.valueOf(value));
         return this;
     }
 
-    public Request<R> param(@NonNull String name, Collection<?> values) {
+    @SuppressWarnings("unused")
+    public Request<R> param(String name, Collection<?> values) {
         this.parametersArray.put(
                 name,
                 values.stream()
@@ -97,18 +106,21 @@ public Request<R> param(@NonNull String name, Collection<?> values) {
         return this;
     }
 
-    public Request<R> expectStatus(@NonNull HttpStatus status) {
+    @SuppressWarnings("unused")
+    public Request<R> expectStatus(HttpStatus status) {
         this.status = status;
         return this;
     }
 
-    public Request<R> basicAuth(@NonNull String username, @NonNull String password) {
+    @SuppressWarnings("unused")
+    public Request<R> basicAuth(String username, String password) {
         this.basicAuth = new UsernameAndPassword(username, password);
         return this;
     }
 
     @SneakyThrows(UnsupportedEncodingException.class)
-    public <T> ItemResponse<T> returnItem(@NonNull Class<T> clazz) {
+    @SuppressWarnings("unused")
+    public <T> ItemResponse<T> returnItem(Class<T> clazz) {
         var res = _execute();
 
         var resString = res.andReturn().getResponse().getContentAsString(StandardCharsets.UTF_8);
@@ -120,14 +132,15 @@ public <T> ItemResponse<T> returnItem(@NonNull Class<T> clazz) {
             return jsonMapper.readValue(resString, javaType);
         } catch (JacksonException e) {
             log.error("Failed to read response as JSON.", e);
-            throw new RuntimeException(e);
+            throw new ResponseBodyException(e);
         }
     }
 
     @SneakyThrows(UnsupportedEncodingException.class)
+    @SuppressWarnings("unused")
     public <T, M extends Meta> ItemResponseWithMeta<T, M> returnItem(
-            @NonNull Class<T> clazz,
-            @NonNull Class<M> metaClass
+            Class<T> clazz,
+            Class<M> metaClass
     ) {
         var res = _execute();
 
@@ -140,12 +153,13 @@ public <T, M extends Meta> ItemResponseWithMeta<T, M> returnItem(
             return jsonMapper.readValue(resString, javaType);
         } catch (JacksonException e) {
             log.error("Failed to read response as JSON.", e);
-            throw new RuntimeException(e);
+            throw new ResponseBodyException(e);
         }
     }
 
     @SneakyThrows(UnsupportedEncodingException.class)
-    public <T> ListResponse<T> returnList(@NonNull Class<T> clazz) {
+    @SuppressWarnings("unused")
+    public <T> ListResponse<T> returnList(Class<T> clazz) {
         var res = _execute();
 
         var resString = res.andReturn().getResponse().getContentAsString(StandardCharsets.UTF_8);
@@ -157,12 +171,13 @@ public <T> ListResponse<T> returnList(@NonNull Class<T> clazz) {
             return jsonMapper.readValue(resString, javaType);
         } catch (JacksonException e) {
             log.error("Failed to read response as JSON.", e);
-            throw new RuntimeException(e);
+            throw new ResponseBodyException(e);
         }
     }
 
     @SneakyThrows(UnsupportedEncodingException.class)
-    public <T> PagedResponse<T> returnPage(@NonNull Class<T> clazz) {
+    @SuppressWarnings("unused")
+    public <T> PagedResponse<T> returnPage(Class<T> clazz) {
         var res = _execute();
 
         var resString = res.andReturn().getResponse().getContentAsString(StandardCharsets.UTF_8);
@@ -174,11 +189,12 @@ public <T> PagedResponse<T> returnPage(@NonNull Class<T> clazz) {
             return jsonMapper.readValue(resString, javaType);
         } catch (JacksonException e) {
             log.error("Failed to read response as JSON.", e);
-            throw new RuntimeException(e);
+            throw new ResponseBodyException(e);
         }
     }
 
     @SneakyThrows(UnsupportedEncodingException.class)
+    @SuppressWarnings("unused")
     public ErrorResponse returnError() {
         var res = _execute();
 
@@ -188,14 +204,16 @@ public ErrorResponse returnError() {
             return jsonMapper.readValue(resString, ErrorResponse.class);
         } catch (JacksonException e) {
             log.error("Failed to read response as JSON.", e);
-            throw new RuntimeException(e);
+            throw new ResponseBodyException(e);
         }
     }
 
+    @SuppressWarnings("unused")
     public ResultActions returnRaw() {
         return _execute();
     }
 
+    @SuppressWarnings("unused")
     public void execute() {
         _execute();
     }
@@ -204,12 +222,12 @@ public void execute() {
     private ResultActions _execute() {
         var requestBuilder = prepareRequestBuilder();
 
-        ResultActions resultActions = null;
+        ResultActions resultActions;
         try {
             resultActions = mockMvc.perform(requestBuilder);
         } catch (Exception e) {
             log.error("Request execution failed.", e);
-            throw new RuntimeException(e);
+            throw new RequestExecutionException(e);
         }
 
         maybeCheckStatus(resultActions);
@@ -217,8 +235,6 @@ private ResultActions _execute() {
         return resultActions;
     }
 
-    @NonNull
-    @SuppressWarnings("unchecked")
     protected R prepareRequestBuilder() {
         var requestBuilder = getRequestBuilder(url)
                 .content(body)
@@ -249,15 +265,14 @@ protected R prepareRequestBuilder() {
             requestBuilder.param(entry.getKey(), entry.getValue());
         }
 
-        return (R) requestBuilder;
+        return requestBuilder;
     }
 
-    @NonNull
-    protected abstract R getRequestBuilder(@NonNull UrlWithVariables url);
+    protected abstract R getRequestBuilder(UrlWithVariables url);
 
     protected abstract boolean useCsrf();
 
-    protected void maybeCheckStatus(@NonNull ResultActions resultActions) {
+    protected void maybeCheckStatus(ResultActions resultActions) {
         var mvcResult = resultActions.andReturn();
         if (status != null) {
             assertThat(
@@ -271,4 +286,22 @@ protected void maybeCheckStatus(@NonNull ResultActions resultActions) {
                     .isEqualTo(status.value());
         }
     }
+
+    public static class RequestBodyException extends RuntimeException {
+        public RequestBodyException(Throwable cause) {
+            super(cause);
+        }
+    }
+
+    public static class ResponseBodyException extends RuntimeException {
+        public ResponseBodyException(Throwable cause) {
+            super(cause);
+        }
+    }
+
+    public static class RequestExecutionException extends RuntimeException {
+        public RequestExecutionException(Throwable cause) {
+            super(cause);
+        }
+    }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/web/request/RequestSecurityAssert.java b/src/main/java/it/aboutbits/springboot/testing/web/request/RequestSecurityAssert.java
index 742f069..3b84012 100644
--- a/src/main/java/it/aboutbits/springboot/testing/web/request/RequestSecurityAssert.java
+++ b/src/main/java/it/aboutbits/springboot/testing/web/request/RequestSecurityAssert.java
@@ -1,11 +1,13 @@
 package it.aboutbits.springboot.testing.web.request;
 
 import org.assertj.core.api.AbstractAssert;
+import org.jspecify.annotations.NullMarked;
 import org.springframework.http.HttpStatus;
 import org.springframework.test.web.servlet.ResultActions;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+@NullMarked
 public final class RequestSecurityAssert extends AbstractAssert<RequestSecurityAssert, ResultActions> {
     RequestSecurityAssert(ResultActions actual) {
         super(actual, RequestSecurityAssert.class);
@@ -15,16 +17,19 @@ public static RequestSecurityAssert assertThatRequest(ResultActions actual) {
         return new RequestSecurityAssert(actual);
     }
 
+    @SuppressWarnings("unused")
     public void wasUnauthorized() {
         var status = actual.andReturn().getResponse().getStatus();
         assertThat(status).isEqualTo(HttpStatus.UNAUTHORIZED.value());
     }
 
+    @SuppressWarnings("unused")
     public void wasDenied() {
         var status = actual.andReturn().getResponse().getStatus();
         assertThat(status).isEqualTo(HttpStatus.FORBIDDEN.value());
     }
 
+    @SuppressWarnings("unused")
     public void wasGranted() {
         var status = actual.andReturn().getResponse().getStatus();
         assertThat(status).isNotEqualTo(HttpStatus.FORBIDDEN.value());
diff --git a/src/test/java/it/aboutbits/springboot/testing/ArchitectureTest.java b/src/test/java/it/aboutbits/springboot/testing/ArchitectureTest.java
new file mode 100644
index 0000000..bd67857
--- /dev/null
+++ b/src/test/java/it/aboutbits/springboot/testing/ArchitectureTest.java
@@ -0,0 +1,20 @@
+package it.aboutbits.springboot.testing;
+
+import com.tngtech.archunit.junit.AnalyzeClasses;
+import com.tngtech.archunit.junit.CacheMode;
+import it.aboutbits.archunit.toolbox.ArchitectureTestBase;
+import org.jspecify.annotations.NullMarked;
+
+@AnalyzeClasses(
+        packages = ArchitectureTest.PACKAGE,
+        cacheMode = CacheMode.PER_CLASS
+)
+@NullMarked
+class ArchitectureTest extends ArchitectureTestBase {
+    static final String PACKAGE = "it.aboutbits.springboot.testing";
+
+    static {
+        // We declare the replacement in this library, so using the base class here is fine.
+        ArchitectureTestBase.BLACKLISTED_CLASSES.remove("net.datafaker.Faker");
+    }
+}
diff --git a/src/test/java/it/aboutbits/springboot/testing/validation/ValidationAssertTest.java b/src/test/java/it/aboutbits/springboot/testing/validation/ValidationAssertTest.java
index 2124dac..db4a08d 100644
--- a/src/test/java/it/aboutbits/springboot/testing/validation/ValidationAssertTest.java
+++ b/src/test/java/it/aboutbits/springboot/testing/validation/ValidationAssertTest.java
@@ -1,5 +1,6 @@
 package it.aboutbits.springboot.testing.validation;
 
+import it.aboutbits.archunit.toolbox.support.ArchIgnoreNoProductionCounterpart;
 import it.aboutbits.springboot.testing.validation.core.BaseRuleBuilder;
 import it.aboutbits.springboot.testing.validation.core.BaseValidationAssert;
 import it.aboutbits.springboot.toolbox.type.ScaledBigDecimal;
@@ -16,9 +17,11 @@
 import jakarta.validation.constraints.PositiveOrZero;
 import jakarta.validation.constraints.Size;
 import lombok.With;
+import org.jspecify.annotations.NonNull;
+import org.jspecify.annotations.NullUnmarked;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
-import org.springframework.lang.Nullable;
 import org.springframework.validation.annotation.Validated;
 
 import java.math.BigDecimal;
@@ -46,6 +49,8 @@
 import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
+@ArchIgnoreNoProductionCounterpart
+@NullUnmarked
 class ValidationAssertTest {
     @With
     public record SomeValidParameter(
@@ -739,7 +744,6 @@ void usingRuleRegistrarShouldWork() {
                 .isCompliant();
     }
 
-
     @SuppressWarnings("checkstyle:MethodLength")
     private static SomeValidParameter getSomeValidParameter() {
         return new SomeValidParameter(
@@ -906,7 +910,7 @@ private static SomeValidParameter getSomeValidParameter() {
         );
     }
 
-    public static final class TestValidationAssert extends BaseValidationAssert<BaseRuleBuilder<?>> {
+    public static final class TestValidationAssert extends BaseValidationAssert<@NonNull BaseRuleBuilder<?>> {
         private TestValidationAssert() {
             super(new TestRuleBuilder());
         }
@@ -915,7 +919,7 @@ public static TestValidationAssert assertThatValidation() {
             return new TestValidationAssert();
         }
 
-        public static final class TestRuleBuilder extends BaseRuleBuilder<TestRuleBuilder> {
+        public static final class TestRuleBuilder extends BaseRuleBuilder<@NonNull TestRuleBuilder> {
         }
     }