java - Writing JSON using Jackson blocks my TimerTask -

i write json every 5th second. i'm using jackson write json, seem block timertask. if don't write json, timertask run every 5th second, when try write json it's blocked , run once. how can fix this?

public class mytimertask extends timertask {      public static void main(string[] args) {          timer timer = new timer();          // execute mytimertask every 5th second         timer.scheduleatfixedrate(new mytimertask(), 1000l, 5 * 1000l);     }      @override     public void run() {         system.out.println("timertask");          // write json system.out         objectmapper mapper = new objectmapper();         try {             mapper.writevalue(system.out, "hello");         } catch (exception e1) {             e1.printstacktrace();         }     } } 

here stack dump timer thread:

"timer-0" prio=6 tid=0x02488000 nid=0x10ec in object.wait() [0x04a6f000]    java.lang.thread.state: timed_waiting (on object monitor)         @ java.lang.object.wait(native method)         - waiting on <0x24577fa8> (a java.util.taskqueue)         @ java.util.timerthread.mainloop(unknown source)         - locked <0x24577fa8> (a java.util.taskqueue)         @ java.util.timerthread.run(unknown source) 

the problem use of system.out, not jackson.