Methods of the System class

 

1  package system;
 2  /** 
3  * exit(int status) Terminates the currently running Java virtual machine.
4                                    
5     gc() Runs the garbage collector
 6                
7     currentTimeMillis() Returns the current time in milliseconds.
8                
9  * @author star
 10  *
 11   */ 
12  public  class SystemDemo1 {
 13  
14      public  static  void main(String[] args) {
 15  //         System.out.println("hello");
 16  //         System.exit( 0);
 17  //        System.out.println("world");
18 
19         
20         //获取当前系统时间
21 //        long time = System.currentTimeMillis();
22 //        System.out.println(time);
23 //        System.out.println(Long.MAX_VALUE);
24         
25         long start = System.currentTimeMillis();
26         int sum = 0;
27         for(int i = 0;i<1000000;i++){
28 //            System.out.println("hello" + i);
29             sum += i;
30         }
 31          
32          long end = System.currentTimeMillis();
 33          System.out.println("Total time: " + (end - start) + "milliseconds" + sum);
 34      }
 35  
36 }