java - Threads running at same time instance -

i have requirement threading need initiate thread run continuously doing db operations . second thread present needs run every 30 secs. job of second thread killing first thread , start new instance of first thread.

i tried several ways achieve not able same.

public class threadmain {  public static void main(string[] args) throws interruptedexception, brokenbarrierexception{      final cyclicbarrier gate = new cyclicbarrier(3);      thread t1 = new thread(){         public void run(){             try {                 gate.await();                 while(true)                 {                      system.out.println("thread1");                       break;                  }             } catch (interruptedexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (brokenbarrierexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }          }};     thread t2 = new thread(){         public void run(){             try {                 gate.await();                 while(true)                 {                      system.out.println("continiously running thread:-thread2");                       }             } catch (interruptedexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (brokenbarrierexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }          }};      t1.start();     t2.start(); 

this seems work nicely:

// thread runs forever. volatile static thread foreverthread = null;  static class forever implements runnable {      @override     public void run() {         try {             while (true) {                 thread.sleep(1000);                 system.out.println("for ever!");             }         } catch (interruptedexception ex) {             // quit if interrupted.         }     }  }  // stop thread if running. private static void stopforeverthread() throws interruptedexception {     // skip if non-existent.     if (foreverthread != null) {         // make sure no-one else doing it.         synchronized (foreverthread) {             // still not null?             if (foreverthread != null) {                 // interrupt it.                 foreverthread.interrupt();                 // wait finish.                 foreverthread.join();                 // clear it.                 foreverthread = null;             }         }     } }  private static void restartforeverthread() throws interruptedexception {     system.out.println("restarting...");     // stop if running.     stopforeverthread();     // start again.     foreverthread = new thread(new forever());     foreverthread.start();     system.out.println("restarted"); }  public static void start() throws interruptedexception {     // start up.     restartforeverthread();     // timed event restart it.     timer restarttimer = new timer(true);     restarttimer.scheduleatfixedrate(             new timertask() {                 @override                 public void run() {                     try {                         // restart every few seconds.                         restartforeverthread();                     } catch (interruptedexception ex) {                         // interrupted during restart - log it.                     }                 }                 // every few seconds.             }, 0, 10 * 1000);  }  public static void main(string args[]) {     try {         // start up.         start();         // hang around while - see happens.         thread.sleep(60 * 1000);     } catch (throwable t) {         t.printstacktrace(system.err);     } }