public class Singleton {
private static Singleton instance = null;
private Singleton(){}
public static Singleton getInstance(){
if(instance == null ) {
instance = new Singleton();
}
return instance;
}
}
public class Singleton {
private static Singleton instance = null;
private Singleton(){}
public static synchronized Singleton getInstance(){
if(instance == null ) {
instance = new Singleton();
}
return instance;
}
}
public class Singleton {
private static Singleton instance = new Singleton();
private Singleton(){}
public static Singleton getInstance(){
return instance;
}
}
public class Singleton {
private static class SingletonHolder {
public static Singleton instance = new Singleton();
}
private Singleton(){}
public static Singleton getInstance(){
return Singleton.SingletonHolder.instance;
}
}
public class Singleton {
private Singleton(){}
public static Singleton getInstance(){
return Single.instance.getInstance();
}
private static enum Single {
instance;
private Singleton single;
private Single(){
single = new Singleton();
}
public Singleton getInstance(){
return single;
}
}
}
public class Singleton {
private static volatile Singleton instance = null;
private Singleton(){}
private static Singleton getInstance() {
if(instance == null) {
synchronized (Singleton.class) {
if(instance == null){
instance = new Singleton();
}
}
}
return instance;
}
}