Is it required to use thread wait() and notify() inside a synchronized block?

Question

In Java, is it required to use thread wait() and notify() within a synchronized block?

This question is confusing because if you are going to use wait() it must be inside a synchronized block, but if you are going to use a synchronized block it is not mandatory to have a wait/notify, which situation is the one you are asking about? — ilcavero, Feb 13 '13 at 23:14
When the threads need to pass data around, it’s not enough to say “don’t run on the same data while I am running” but each thread must tell another thread that “I have some data for you”. In this case we require thread wait and notify. So synchronized behavior is different from wain/notify — DeadManSpirit, Feb 13 '13 at 23:17

score 4 · Accepted Answer · edited May 23 '17 at 12:04

No. Java will automatically ensure the marked section is entered by one and only one thread.

http://tutorials.jenkov.com/java-concurrency/synchronized.html

see also this question: java: wait(), notify() and synchronized blocks

Hmm.. seems to be some language issues.

You are not required to use wait and notify in a synchronized block, but if you want to use wait and notify, they must be used within a synchronized block.

score 2 · Answer 2 · edited May 23 '17 at 10:32

2

in short, yes. The thread must own the object's monitor before calling wait or notify.

edited May 23 '17 at 10:32

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answered Feb 13 '13 at 23:06

Ralf H

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Is it required to use thread wait() and notify() inside a synchronized block?

2 Answers2