System.exit is not thread-safe on Linux?

[duzer]

I've just switched from Oracle JDK 1.6, to Open JDK 1.7.0_03, and I've hit a rather remarkable deadlock on exit:\[code\]java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Thread.join(Thread.java:1258) - locked <0x8608dda0> (a sun.awt.X11.XToolkit$1$1) at java.lang.Thread.join(Thread.java:1332) at java.lang.ApplicationShutdownHooks.runHooks(ApplicationShutdownHooks.java:106) at java.lang.ApplicationShutdownHooks$1.run(ApplicationShutdownHooks.java:46) at java.lang.Shutdown.runHooks(Shutdown.java:123) at java.lang.Shutdown.sequence(Shutdown.java:167) at java.lang.Shutdown.exit(Shutdown.java:212) - locked <0x8603df28> (a java.lang.Class for java.lang.Shutdown) at java.lang.Runtime.exit(Runtime.java:107) at java.lang.System.exit(System.java:960)\[/code\]It appears that you must call System.exit from the AWT event queue. Is this for real? There is no documentation of a thread requirement in the Sun docs Runtime.exitI've hit other surprising cases where getting the AWT tree lock is required only on Linux, but this one takes the cake. Is this a bug, or have I just missed something in the documentation?