Is it possible for a thread to Deadlock itself?

Question

Is it technically possible for a thread in Java to deadlock itself?

I was asked this at an interview a while back and responded that it wasn\'t possible but the inte

Answer 1

Although the comments here are being pedantic about "deadlock" happening if at least two threads/actions are competing for the same resource...I think the spirit of this question was to discuss a need for Reentrant lock - especially in context of "recursive" locking

Here's an example in python (I am certain the concept stays the same in Java): If you change the RLock to Lock (i.e. reentrant lock to lock, the thread will hang)

import threading

"""
Change RLock to Lock to make it "hang"
"""
lock = threading.Condition(threading.RLock())


def print_list(list):
    lock.acquire()
    if not list:
        lock.release()
        return
    print(list[0])
    print_list(list[1:])
    lock.release()


print_list([1, 2, 3, 4, 5])