When starting a TestSuite in multithreaded mode we seem to encounter a race condition:

10.11.2010 15:00:30 net.sf.sahi.test.ProcessHelper kill
INFO: Kill: null
java.lang.NullPointerException
at net.sf.sahi.test.ProcessHelper.killPIDs(ProcessHelper.java:172)
at net.sf.sahi.test.ProcessHelper.kill(ProcessHelper.java:165)
at net.sf.sahi.test.BrowserLauncher.kill(BrowserLauncher.java:80)
at net.sf.sahi.test.TestLauncher.kill(TestLauncher.java:122)
at net.sf.sahi.test.SahiTestSuite.notifyComplete2(SahiTestSuite.java:175)
at net.sf.sahi.test.SahiTestSuite.notifyComplete(SahiTestSuite.java:164)
at net.sf.sahi.rhino.RhinoScriptRunner.stop(RhinoScriptRunner.java:211)
at net.sf.sahi.rhino.RhinoScriptRunner.run(RhinoScriptRunner.java:132)
at java.lang.Thread.run(Unknown Source)
10.11.2010 15:00:32 net.sf.sahi.test.ProcessHelper$PIDGatherer run
INFO: PIDs: [3540]; 3282 ms

PID 3540 is never killed.

Modifying ProcessLauncher.kill as follows solved our problem:
public void kill() {
try {
lock.acquire();
if (pids == null) {
logger.warning("PIDs unset, no PIDs to kill. " + this.toString());
return;
}
logger.info("Kill: " + pids + " " + this.toString());
for (int i = 0; i < 4; i++) {
killPIDs();
if (waitTillPIDsGone(pids, 3000))
return;
}
} catch (InterruptedException e1) {
e1.printStackTrace();
} finally {
lock.release();
}
}