checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN" "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
    <module name="SuppressionFilter">
        <property name="file" value="checkstyle-suppressions.xml" />
    </module>
    <module name="SuppressWarningsFilter" />
    <!-- Make messages show file/line/col -->
    <module name="SeverityMatchFilter" />
    <!-- Line length -->
    <module name="LineLength">
        <property name="max" value="100" />
        <property name="ignorePattern" value="^package\s|^import\s|https?://|@|^\s*\*" />
    </module>
    <module name="TreeWalker">
        <module name="SuppressWarningsHolder" />
        <!-- =========================================
         MEMBER ORDERING
         ========================================= -->
        <module name="DeclarationOrder" />
        <!-- =========================================
         FORMATTING
         ========================================= -->
        <!-- Curly brace style (same-line open, etc.) -->
        <module name="LeftCurly">
            <property name="option" value="eol" />
        </module>
        <module name="RightCurly">
            <property name="option" value="same" />
        </module>
        <!-- Whitespace rules (method headers/calls, operators, etc.) -->
        <module name="WhitespaceAround" />
        <module name="WhitespaceAfter" />
        <!-- One statement per line -->
        <module name="OneStatementPerLine" />
        <!-- Require braces on control statements -->
        <module name="NeedBraces" />
        <!-- Empty lines: “blank line before each method comment” cannot be done perfectly
         but this enforces separation between members. -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true" />
            <property name="allowMultipleEmptyLines" value="false" />
        </module>
        <!-- Enforces 4 spaces even though 3 is fine -->
        <module name="Indentation">
            <property name="basicOffset" value="4" />
            <property name="braceAdjustment" value="0" />
            <property name="caseIndent" value="4" />
            <property name="lineWrappingIndentation" value="8" />
            <property name="throwsIndent" value="8" />
            <property name="arrayInitIndent" value="4" />
        </module>
        <!-- =========================================
         NAMING
         ========================================= -->
        <module name="TypeName" />
        <module name="MethodName" />
        <module name="ParameterName" />
        <module name="LocalVariableName" />
        <module name="MemberName" />
        <!-- Constants SCREAMING_CASE -->
        <module name="ConstantName" />
        <!-- =========================================
         FIELDS / ACCESS MODIFIERS
         ========================================= -->
        <module name="VisibilityModifier">
            <property name="allowPublicFinalFields" value="true" />
            <property name="allowPublicImmutableFields" value="true" />
            <property name="protectedAllowed" value="false" />
            <property name="packageAllowed" value="false" />
        </module>
        <!-- =========================================
         EXCEPTIONS / CONTROL FLOW FORBIDDEN FEATURES
         ========================================= -->
        <!-- No lambdas / method references (Java 8) -->
        <module name="IllegalToken">
            <property name="tokens" value="LAMBDA,METHOD_REF" />
        </module>
        <module name="MatchXpath">
            <property name="query" value="//OBJBLOCK/VARIABLE_DEF[./ASSIGN and not(./MODIFIERS/FINAL)]" />
            <message key="matchxpath.match" value="Do not initialize fields at declaration; initialize in constructors (or a factory)." />
        </module>
        <!-- No 'var' keyword (Java 10 local var inference) -->
        <module name="RegexpSinglelineJava">
            <property name="format" value="(^|\s)\bvar\b\s+\w+" />
            <property name="message" value="The 'var' keyword is not allowed." />
        </module>
        <!-- =========================================
         JavaDocs/Header Comment
         ========================================= -->
        <!-- Require Javadoc on all types -->
        <module name="MissingJavadocType">
            <property name="scope" value="private" />
        </module>
        <!-- Require Javadoc on all methods (ignore main) -->
        <module name="MissingJavadocMethod">
            <property name="scope" value="private" />
            <property name="allowMissingPropertyJavadoc" value="false" />
            <property name="ignoreMethodNamesRegex" value="main" />
        </module>
        <!-- =========================================
         Beyond CSE 12X 
         ========================================= -->
        <module name="JavadocMethod">
            <property name="accessModifiers" value="public,protected,package,private" />
            <property name="allowMissingParamTags" value="false" />
            <property name="allowMissingReturnTag" value="false" />
            <property name="validateThrows" value="true" />
        </module>
        <!-- Require Javadoc for public constructors -->
        <module name="JavadocMethod">
            <property name="accessModifiers" value="public,protected,package,private" />
            <property name="tokens" value="CTOR_DEF" />
            <property name="allowMissingParamTags" value="false" />
            <property name="validateThrows" value="true" />
        </module>
        <module name="EmptyStatement" />
        <module name="JavadocStyle">
            <property name="checkFirstSentence" value="true" />
        </module>
    </module>
</module>