/* * 这是多行注释 * */ import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.Scanner; //导包 public class HelloWorld { public static void main(String[] args) { //这是单行注释 System.out.println("helloworld!"); System.out.println("hello"); // Math.random(); Scanner scann = new Scanner(System.in); Map map = new HashMap(); Date date = null; } public void method(){ } }