### Question:
ResourceLeakDetector { public final ResourceLeakTracker<T> track(T obj) { return track0(obj); } @Deprecated  ResourceLeakDetector(Class<?> resourceType); @Deprecated  ResourceLeakDetector(String resourceType); @Deprecated  ResourceLeakDetector(Class<?> resourceType, int samplingInterval, long maxActive); @SuppressWarnings("deprecation")  ResourceLeakDetector(Class<?> resourceType, int samplingInterval); @Deprecated  ResourceLeakDetector(String resourceType, int samplingInterval, long maxActive); @Deprecated static void setEnabled(boolean enabled); static boolean isEnabled(); static void setLevel(Level level); static Level getLevel(); @Deprecated final ResourceLeak open(T obj); final ResourceLeakTracker<T> track(T obj);  }### Answer:
@Test(timeout = 60000) public void testConcurrentUsage() throws Throwable { final AtomicBoolean finished = new AtomicBoolean(); final AtomicReference<Throwable> error = new AtomicReference<Throwable>(); Thread[] threads = new Thread[50]; final CyclicBarrier barrier = new CyclicBarrier(threads.length); for (int i = 0; i < threads.length; i++) { Thread t = new Thread(new Runnable() { Queue<LeakAwareResource> resources = new ArrayDeque<LeakAwareResource>(100); @Override public void run() { try { barrier.await(); for (int b = 0; b < 1000 && !finished.get(); b++) { for (int a = 0; a < 100; a++) { DefaultResource resource = new DefaultResource(); ResourceLeakTracker<Resource> leak = DefaultResource.detector.track(resource); LeakAwareResource leakAwareResource = new LeakAwareResource(resource, leak); resources.add(leakAwareResource); } if (closeResources(true)) { finished.set(true); } } } catch (InterruptedException e) { Thread.currentThread().interrupt(); } catch (Throwable e) { error.compareAndSet(null, e); } finally { closeResources(false); } } private boolean closeResources(boolean checkClosed) { for (;;) { LeakAwareResource r = resources.poll(); if (r == null) { return false; } boolean closed = r.close(); if (checkClosed && !closed) { error.compareAndSet(null, new AssertionError("ResourceLeak.close() returned 'false' but expected 'true'")); return true; } } } }); threads[i] = t; t.start(); } for (Thread t: threads) { t.join(); } DefaultResource.detector.assertNoErrors(); assertNoErrors(error); }