Comments on: Java Concurrency Bugs #2 – what to synchronize on

By: Alex

Alex — Wed, 03 Nov 2010 01:26:16 +0000

@Jack: As I say above, it’s generally a bad idea to synchronize on a string, especially if you don’t how it was created. If that String was interned or created as a “abc” string literal, then another String elsewhere is identical (due to interning) and you might be sharing lock scopes when you don’t expect it. It is possible for locking on Strings to be safe if you know how those strings are created (for example with new String(…)).

By: Jack

Jack — Tue, 02 Nov 2010 23:27:16 +0000

public doSomething(String st) {

synchronized(st) {
….
}

}

Can I do the above? Or do you see any issues?

Thanks

By: Dan Lewis

Dan Lewis — Fri, 30 Jan 2009 14:17:43 +0000

Thanks for sharing these

By: Alex

Alex — Fri, 30 Jan 2009 04:08:24 +0000

@Tuure: I don’t think it’s misleading. But it may be badly worded. :) I hear what you’re saying. That’s the benefit of putting this stuff on the web and getting feedback of course. By the time it makes it into a talk I’ll have figured out what the hell I’m talking about. Thanks…

By: Tuure Laurinolli

Tuure Laurinolli — Fri, 30 Jan 2009 00:49:45 +0000

Number one is a bit misleading. “#1: Don’t synchronize on a variable you’re reassigning” would be better, but not quite spot-on accurate either since you’re synchonizing on the object and not the variable, which is what causes the problem in the first place :)