Proguard.java

public class TestProguardActivity extends AppCompatActivity {
	private final Executor background = Executors.newSingleThreadExecutor();

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		final TextView view = new TextView(this);
		setContentView(view);

		TestClass.testMethod(view);

		view.append("Methods:\n");
		AnotherTestClass.printMethods(view);

		final AnotherTestClass o = new AnotherTestClass();
		background.execute(new Runnable() {
			@Override
			public void run() {
				o.waitForNotify(view);
			}
		});
		view.postDelayed(new Runnable() {
			@Override
			public void run() {
				synchronized (o) {
					o.notify();
				}
			}
		}, 5000);
	}
}

final class TestClass {

	public static void testMethod(TextView view) {
		view.append("testMethod called\n\n");
	}
}

final class AnotherTestClass {

	public static void printMethods(TextView view) {
		for (Method method : AnotherTestClass.class.getMethods()) {
			view.append(method.getName());
			view.append("\n");
		}
	}

	public void waitForNotify(final TextView view) {
		try {
			final long waiting = System.currentTimeMillis();
			synchronized (this) {
				wait();
			}
			final long running = System.currentTimeMillis();
			view.post(new Runnable() {
				@Override
				public void run() {
					view.append("\n\nwaiting at " + waiting);
					view.append("\nrunning at " + running + " after " + (running - waiting) + "ms");
				}
			});
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}