Java thread-safe singleton

SingletonClass.java

public class SingletonClass {
    // dummy object for synchronization
    private static final Object sLock = new Object();

    // single instance of the class
    private static SingletonClass INSTANCE;

    public static SingletonClass getInstance() {
        // force threads to wait until synchronized block completes
        synchronized (sLock) {
            if (INSTANCE == null) {
                INSTANCE = new SingletonClass();
            }
            return INSTANCE;
        }
    }

    // prevent instantiation outside of class
    private SingletonClass() {}
}