java的第一个程序

如果一个包里面含有main，都可以作为一个单独的程序来执行。

使用java application

1.

package src;
import java.util.*;
public class second {
 public static void main(String[] args){
  System.out.println(new Date());
  Properties p = System.getProperties();
  System.out.println("---Memory Usage22222222222");
  p.list(System.out);
  
  Runtime rt =  Runtime.getRuntime();
  System.out.println("Total Memory = "
    + rt.totalMemory()
    + " Free Memory = "
    + rt.freeMemory()
    );
 }
}

2.

package first;
import java.util.*;
public class name {
 public static void main(String[] args){
  System.out.println(new Date());
  Properties p = System.getProperties();
  p.list(System.out);
  System.out.println("---Memory Usage");
  Runtime rt =  Runtime.getRuntime();
  System.out.println("Total Memory = "
    + rt.totalMemory()
    + " Free Memory = "
    + rt.freeMemory()
    );
 }

}