[GROOVY-4534] Thread.join appears to not work correctly in at least one special case

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.7.5
• Fix Version/s: 1.7.6, 1.8-beta-3
• Environment: 32 bit Windows XP, Groovy 1.7.5. Also using Eclipse 3.6 + groovy plugin
• Assignee: Roshan Dawrani
• Reporter: Reid Nimz
• Created: 24/Nov/10 14:35
• Updated: 15/Dec/10 16:57
• Resolved: 25/Nov/10 08:00

Description

While writing test code for a networking component I ran into the following issue. I created a thread to read from a socket, started it and then wrote to a client socket. After writing called thread.join() and expected it to finish executing my server socket thread before continuing. Instead what I get is non-deterministic behavior. Sometimes the thread finishes sometimes not. Since the thread isn't doing much if I add a sleep the code works (my work around in my test code). To be clear I'm not expecting that the print statements execute in any particular order - I'm concerned that the lines won't get added to the list and thus the current thread hasn't actually waited for the spawned thread to exit.

I've attached a sample groovy class that exhibits the problem and the equivalent Java code that does not have the issue.