Singleton Design Pattern

Approach 1: Regular singleton

package

patterns;

public

class Singleton {

private static Singleton myObject = null;

private Singleton() {

}

public static synchronized Singleton getInstance() {

if (myObject== null) {

myObject = new Singleton();

}

return myObject;

}

}


Approach 2: Double Lock check

package

patterns;

public

class SingletonDoubleLock {

private static SingletonDoubleLock myObject = null;

private SingletonDoubleLock() {

}

public static SingletonDoubleLock getInstance() {

if (myObject == null) {

synchronized (SingletonDoubleLock.class) {

if (myObject == null) {

myObject = new SingletonDoubleLock();

}

}

}

return myObject;

}

}

Aproach 3: Early Initilization

package

patterns;

public

class SingletonEarly {

private static SingletonEarly myObject = new SingletonEarly();

private SingletonEarly() {

}

public static SingletonEarly getInstance() {

return myObject;

}

}