单例模式+锁

public class Singleton {

	/**
	 * @param args 单例模式+加锁操作
	 */
	
	private static Singleton instance;
	
	private Singleton() {
		
	}
	
	public static Singleton getinstance() {
		 synchronized(Singleton.class){

			
	
		if (instance==null) {
			instance=new Singleton();
		}
		
		}
		return instance;
	}
	
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Singleton s1=Singleton.getinstance();
		Singleton s2=Singleton.getinstance();
		if (s1==s2) {
			System.out.println("=======");
			
		}
	}

}