fix: change Wallet.lock to ReentrantReadWriteLock

Author: HashEngineering

core/src/main/java/org/bitcoinj/utils/Threading.java

@@ -31,6 +31,7 @@
 import java.lang.management.ThreadMXBean;
 import java.util.concurrent.*;
 import java.util.concurrent.locks.ReentrantLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 /**
  * Various threading related utilities. Provides a wrapper around explicit lock creation that lets you control whether
@@ -192,6 +193,13 @@ public static CycleDetectingLockFactory.Policy getPolicy() {
         return policy;
     }
 
+    public static ReentrantReadWriteLock readWriteLock(String name) {
+        if (Utils.isAndroidRuntime() && useDefaultAndroidPolicy)
+            return new ReentrantReadWriteLock(true);
+        else
+            return factory.newReentrantReadWriteLock(name);
+    }
+
     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // Generic worker pool.