Singleton lazy vs eager instantiation

Question

If a singleton is implemented as follows,

class Singleton {
    private static Singleton instance = new Singleton();

    public static Singleton getInstance         


        

Answer 1

For lazy loading singleton instance, I am using as below.

class Singleton {
private static Singleton instance;
private Singleton(){

}
public static Singleton getInstance() {
    if(null==instance){
        synchronized(Singleton.class){
            if(null==instance){
                instance = new Singleton();
            }
        }
    }
    return instance;
}
}