Potential Thread Problem with JVM (1.4.2_05)

Question

This junit test fails on 1.4.2_05 (running on Windows XP), is there a problem with the code or the JVM?
public class BadJVMTest extends junit.framework.TestCase {
  static byte[] b = new byte[] { -1, 1 };
  public int m2(int offset) {
    while (true) {
      if (b[offset] >= 0)
        return offset + 1;
      offset++;
  class Inner {
    int fOffset = 0;
    public void m1() {
      fOffset = m2(fOffset);
      if (fOffset == 0)
        throw new RuntimeException("Internal Error.");
  private class ReadThread extends Thread {
    int failed = 0;
    public void run() {
      for (int i = 0; i < 100000; i++) {
        try {
          new Inner().m1();
        } catch (Throwable t) {
          failed++;
          System.err.println("Problem on call number " + (i + 1) + " (" + t + ")");
  public void test() throws Exception {
    int numOfThreads = 100;
    ReadThread threads[] = new ReadThread[numOfThreads];
    for (int i = 0; i < numOfThreads; i++) {
      threads[i] = new ReadThread();
      threads.start();
for (int i = 0; i < numOfThreads; i++) {
threads[i].join();
for (int i = 0; i < numOfThreads; i++) {
assertEquals(0, threads[i].failed);

Answer 1

Nothing jumps out at me about the code (other than
its general convolutedness, which I assume you're
aware of).
What, exactly, are you observing? I assume it's that
fOffset is zero after calling m2(), so you're
throwing the RTE, right?Which does look like a bug to me, however, there are parts of nested class arcania that are beyond my paltry knowledge, so I may be basing that on faulty assumptions.