The problem here is that the code for finding local VMs is not looking for the data in the correct place.
When a JVM is started it will create the perf-data file in a user-specific directory inside /tmp (*). The code in the JDK (PerfDataFile.java) that lists all active JVMs looks for the user-specific directory inside java.io.tmpdir. If a user sets -Djava.io.tmpdir on the command line, the code in PerfDataFile will look in the wrong place. (*) It's a little bit more complex. /tmp is used on Linux and Solaris. On OS X and Windows, there are user-specific temp directories that should be used, and so the VM queries the OS for these paths. The solution would be for PerfDataFile to use the same locations as the VM creates them in. The simplest way to guarantee that the same directory is used is to ask the VM to provide the location. Thus I have introduced a new JVM_ function: JVM_GetTemporaryDirectory. (Since this change touches both hotspot and jdk repos I will submit the hotspot part first under a different bug id (provided that the review goes well)). The newly added test starts two VM with all possible combinations of setting and not setting java.io.tmpdir to verify that the mechanism is indeed not looking at that variable. I also removed an if-statement in BasicTests.java which would have found this issue a long time ago had it not been there. Thanks, /Staffan
