External process destroy on Windows XP

Question

Hello friends.
I have a small program that launches external process (another java program), reads and processes process output until the process is destroyed (terminates). The program works fine on Windows 2000 - when external java program launched as separate Process terminates, an inputStream.readLine() call throws exception, and my program can continue. However on XP when external process terminates, it is not unloaded from memory, and inputStream.readLine() blocks forever...
I run under lates JVM 1.4... Any ideas why? Has anyone encountered this problem before?
try {                          
   Process p=Runtime.getRuntime().exec("java SomeProgram");
   in=new BufferedReader(new InputStreamReader(p.getInputStream()));
   while ((s=in.readLine())!=null) { // blocks on XP, works on Win2000
      // Process input
} catch(IOException ioe) {
} catch (Exception e) {
}Any help appreciated.

Answer 1

I have a similar problem with a small Java program running on Linux, so it may not be OS specific. The code is similar to yours, except that the file being read is produced by a third party. The third party claims to produce a new file every 5 minutes, and it takes about 30 seconds for them to produce the file.
The program is supposed to run indefinitely -- it reads the file, then sleeps for 5 minutes, then reads the file again.
Every so often, (like once every 24-36 hours), the program hangs indefinitely at the readLine() call.
What's driving me crazy is that I've used the exact same idiom in numerous other circumstances and I've never encountered this problem.
At first I thought that perhaps the file was being changed while my program was reading it. But under those circumstances I would have thought I'd get some kind of IOException, and I don't.
I'm going to explore using the ready() method of BufferedReader... but I'm not sure if that will solve the problem.
I'd also be very greatful for any input on this matter!
- Dean