In this example we will show how to use Private Constructor to develop singleton class in Java.
Source Code
package com.beginner.examples;
public class StaticInnerSingletonExample {
public static void main(String[] args){
// get singleton instance
Singleton s = Singleton.getInstance();
s.test();
}
}
class Singleton {
private static volatile Singleton singleton;
private Singleton() {}
public static Singleton getInstance() {
// Double-Check
if (singleton == null) {
synchronized (Singleton.class) {
if (singleton == null) {
singleton = new Singleton();
}
}
}
return singleton;
}
public void test(){
System.out.println("It is a singleton example.");
}
}
Output:
It is a singleton example.