public class Foo {

	private static final instance = new Foo();

	private final Object barGetterLock = new Object();
	private Bar barObject = null;

	private static Foo getInstance() {
		return instance;
	}

	private Foo() {
		// ... something here ...
	}

	// This is a thread-safe lazy getter
	public Bar getBarObject() {
		if (barObject == null) {
			synchronized (barGetterLock) {
				/* Please note that barObject == null is tested again
				 * This way, we can be sure that bar object will not be
				 * initialized twice.
				 *
				 * Using the synchronized block before the first if works,
				 * too, but when barObject is yet constructed and initialized,
				 * using the synchronized block there will just be slower and
				 * not useful.
				 */
				if (barObject == null) {
					// Create the bar object
					barObject = new Bar();
					// Initialize the bar object, if needed ...
				}
			}
		}

		return barObject;
	}

}