concurrency - Java thread id not changing -

i'm trying unit test class containing threadlocal , wish make tests not affect each other starting new thread in each test. however, still do, , don't understand why.

@test public void testthread() {     system.out.println(thread.currentthread().getid());     new thread(){         @override         public void run(){             system.out.println(thread.currentthread().getid());         }     }.run(); } 

output:

1 1 

can explain why ids same though new thread started?

you should call start method on thread, not run method. if call run, running in same thread.