JAVA中的main函数

package com.han;

public class HanTest {
	public static void main(String[] args){
		if(args==null){
			throw new NullPointerException("The input is \"null\"");
		}else if((args.length!=1&&args.length!=2)){
			Throwable cause=new Throwable("You have to input 1 or 2 String arguments");
			throw new IllegalArgumentException("Wrong numbers of args",cause);
			//throw new IllegalArgumentException("Wrong numbers of args");
		}else if(args.length==1){
			System.out.println(args[0]);
		}else if(args.length==2){
			System.out.println(args[0]);
			System.out.println(args[1]);
		}
	}
}

package com.han;
public class HanTest2 {
	public static void main(String[] args){
		String[] input={"han"};
		//HanTest.main(null);
		HanTest.main(input);
	}
}