How to detect deadlock ? Timeout in synchronized block?

Question

I’m debugging a Java application that runs several threads. After a while of watching the log it seems that one of those threads is not running anymore. My guess is that the

Answer 1

Rather than adding extra code for debugging, you could use a debugging tool or profiler.

One option is to use something like JConsole (comes with the JDK) which includes a button called "Detect Deadlock" (at least it does in Java 6, I don't think it works in Java 5). Another option is to generate a thread dump to the console - on Unix you can type "kill -3 " while on Windows CTRL+BRK will work. Other profiling tools such as VisualVM (also in the JDK) can help. Finally there is JCarder which is "an open source tool for finding potential deadlocks in concurrent multi-threaded Java programs".