下面两种形式是什么？

Question

public class Test02{
private Test02(){}
private static Test02 instance=new Test02();
public static Test02 getInstance(){
return instance;
}
}
第二种：
public class Test02{
private Test02(){}
private static Test02 instance=null;
public static synchronized Test02 getInstance(){
if(instance==null){
instance=new Test02();
}
return instance;
}
}

Answer 1

单例模式
http://www.blogjava.net/wangchenyang/archive/2011/09/05/363081.html