Thread.sleep(timeout) is influenced by changes to System time on *_Linux_*.
   
    Tested both on:

        Red Hat Linux release 9 (Shrike)

        Kernel 2.4.20-8 on an i686

    and

       Red Hat Enterprise Linux ES release 3 (Taroon Update 4)



    The test is simple,

    call Thread.sleep(15000) and change the time two hours back

    i.e. start at 13:00 call thread.sleep and at 13:05 change the time to 11:05

    you will notice that the sleep does not return at 11:15, not even when the time

    is then fixed back to 13:15


        The test case is simple,

        System.out.println("Press key before sleeping for 15 seconds...");
        System.in.read();
        Thread.sleep(15000);
        System.out.println("Woke-up.");

        ---
        e.g.
          run the test, Press <Enter> at 11:34:00 (00 seconds)
          At 11:34:05 change the clock to 09:34:05 (two hours back)
          Expected result: at 09:34:15 the thread will wake up.

          If the same test is conducted on Windows machine then it works.
          If the clock is set to a _future _time, the test works also for linux.

          I have tested this with the following JDKs:
          1. Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_03-b07)
             Java HotSpot(TM) Client VM (build 1.5.0_03-b07, mixed mode, sharing)
                        [ FAILED ]
          2. Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
             Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)
                        [ FAILED ]
          3. Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_07-b05)
             Java HotSpot(TM) Client VM (build 1.4.2_07-b05, mixed mode)
                        [ PASSED ]
        ---
        Please note that this same test _*PASSED*_ on build 1.4.2_07-b05.

        Please find attached are the following:
        Tester.java - test case
        specification.txt - machine specification
        threadDump.txt - thread dump while thread.sleep didn't wake up