利用反射绕过单例（singleton）模式

例子

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

class zhu1
{
	 private zhu1()
	{
		
	}
	 private static zhu1 a=null;
	 public static zhu1 getinstance()
	 {
		 if(a==null)
		 {
			 a=new zhu1();
		 }
		 return a;
	 }
	 
	}
public class reflectsingleton {
   public static void main(String[]args)
   {
	   Class zhu=zhu1.class;
	   try {
		Constructor c=zhu.getDeclaredConstructor(new Class[]{});
		c.setAccessible(true);
		try {
			zhu1 z1=c.newInstance(new Object[]{});
			System.out.println(z1);
		} catch (InstantiationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	} catch (NoSuchMethodException | SecurityException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
   }
	
}