}
            log.trace("Unregistered resource: {} ({})", resourceId, holder.resourceType);
        }
    }

    /**
     * Check for and report resource leaks
     */
    public void checkForLeaks() {
        if (!leakDetectionEnabled) {
            return;
        }

        // Process phantom references to detect leaks
        Reference<?> ref;
        while ((ref = referenceQueue.poll()) != null) {

        createLeakyResource();

        // Force garbage collection
        System.gc();
        Thread.sleep(200);

        // Check for leaks
        resourceManager.checkForLeaks();

        Map<String, Object> stats = resourceManager.getStatistics();
        // The leak counter may or may not increment depending on GC timing
        assertNotNull(stats.get("totalLeaks"));
    }