public class HelloWorld
{
	public static void main(String[] args){
		System.out.println("HelloWorld");
	}
}
public class HelloWorld
{
	public static void main(String[] args){
		System.out.println("========修改之前========");
		System.out.println("HelloWorld！");
		System.out.println("========修改之后========");

	}
}
Update HelloWorld.java File. add two lines