Memory leak in the slide. Map link for synchronized method

Question

I am creating an interface for the simultaneous execution of methods, abstracting the details of synchronization (to swap for a distributed implementation, when necessary). I created a single jvm implementation that allows you to use strings as a mutex, storing them on a map to ensure that one link is used, even if lines with different links are passed. concurrency seems to be working fine, however, I was surprised to see that the test shows that the link count never decreases. I suggested that using WeakValues ​​() would be sufficient to prevent memory leaks, but it doesn't seem to be that way. Can someone point out what might cause this leak?

public class SynchronousMethodExecutorSynchronizedImpl implements ISynchronousMethodExecutor {

// mutex map to provide string references
final Map<String, String> mutexMap = new MapMaker()
    .weakValues()
    .makeComputingMap(
        new Function<String, String>() {
        @Override
        public String apply(String id) {
            return id;
        }
    });

@Override
public Object doSynchronousMethod(String domain, String id, ISynchronousMethod synchronousMethod) {
    synchronized(mutexMap.get(domain + "." + id))
    {
        return synchronousMethod.execute();
    } 
}

}

, :

public class SynchronousMethodExecutorSynchronizedImplTest extends TestCase {
int counter;
SynchronousMethodExecutorSynchronizedImpl methodExecutor;

@Override
public void before() throws Exception {
    super.before();

    methodExecutor = new SynchronousMethodExecutorSynchronizedImpl();
}

@Test
public void concurrentExecute() throws InterruptedException {
    assertEquals(0, counter);

    for(int i=0; i<1000; i++)
        getConcurrentExecutorThread().start();

    // wait for threads to complete
    Thread.sleep(1000);

    assertEquals(1, methodExecutor.mutexMap.size());

    try
    { 
        final List<long[]> infiniteList = new LinkedList<long[]>(); 

       for(long i = Long.MIN_VALUE; i < Long.MAX_VALUE; i++)
            infiniteList.add(new long[102400]); 

        fail("An OutOfMemoryError should be thrown");
    } 
    catch(OutOfMemoryError e)
    { 

    }

    assertEquals(2000, counter);
    assertEquals(0, methodExecutor.mutexMap.size());
}

// synchronous method
private ISynchronousMethod method = new ISynchronousMethod() {
    @Override
    public Object execute() {
        counter++;  
        return null;
    }
};

/**
 * Executes a line of code.
 * 
 * @return Thread
 */
private Thread getConcurrentExecutorThread() {
    return new Thread() {
        @Override
        public void run() {
            methodExecutor.doSynchronousMethod("TEST", "1", method);
            try
            {
                Thread.sleep(500);
            }
            catch (InterruptedException e)
            {

            }
            methodExecutor.doSynchronousMethod("TEST", new String("1"), method);        
        }

    };
}

}

- , : assertEquals (0, methodExecutor.mutexMap.size());

Answer 1

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Answer 2

, JVM .