The problem

Lock on the class other than the enclosing class of the code block can unintentionally prevent the locked class or other classing using the same lock being used properly. A issue can be caused when the locked class being edited or deleted. And it can also be exhausting and time consuming for the others who is using the same class literal as lock to make sure the synchronized blocks can work properly as expected. Hence locking on the class other than the enclosing class of the synchronized code block is disencouraged by the error prone. Locking on the enclosing class or an instance is a preferred practice.

For example, lock on Other.class rather than Example.class will trigger the error prone warning: ``` class Example {

method() { synchronized (Other.class) { } } } ```

Lock on instance or the enclosing class of the synchronized code block will not trigger the warning: ``` class Example {

method() { synchronized (Example.class) {} synchronized (this) {} } } ```

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("LockOnNonEnclosingClassLiteral") to the enclosing element.