MemoryLeakChecker.java

import org.junit.Assert;
import java.lang.ref.WeakReference;

public class MemoryLeakChecker<T> {

    private static final int MAXGC = 50;

    private final WeakReference<T> reference;
    private final int calls;

    public MemoryLeakChecker(T object) {
        this.reference = new WeakReference<T>(object);
        this.calls = MAXGC;
    }

    public MemoryLeakChecker(T object, int maxGCCalls) {
        this.reference = new WeakReference<T>(object);
        this.calls = maxGCCalls;
    }

    public T get() {
        return reference.get();
    }

    public boolean isObjectGarbageCollected() {
        return reference.get() == null;
    }

    public int getMaxGCCalls() {
        return calls;
    }

    public void assertObjectIsGarbageCollected() {
        Runtime runtime = Runtime.getRuntime();
        for (int i = 0; i < calls; i++) {
            runtime.runFinalization();
            runtime.gc();
            if (get() == null) { break; }
            try { Thread.sleep(200); } catch (InterruptedException e) {}
        }
        Assert.assertNull("After " + calls + " Garbage collection, object isn't garbage collected yet :'(", get());
    }
}