I'm trying to run a Java application in my 64-bit UML. Unfortunately I have experienced a lot of SIGSEGV's when running my application which makes it next to unusable (it crashes maybe 80% of the time). The only way I have found to make the SIGSEGV's go away has been to disable the Java HotSpot compiler completely (running my application in interpreted mode). 

However, in interpreted mode I have observed other strange Java exception problems, which I have never seen when running my application outside the UML. After a lot of googling I have found a small test program ("Test.java") which can easily provoke the problem (at least when run in interpreted mode).

The original test program can be found here:


I have tried the test program on a few other hosts and OS:s (Linux, Windows and also VirtualBox and XEN Linux instances) but still haven't seen it fail outside the UML.

My UML is running on Red Hat Enterprise Linux Server release 5.4 (Tikanga).

uml-22-241>uname -a
Linux uml-22-241 2.6.37 #1 Fri Apr 8 11:03:19 CEST 2011 x86_64 GNU/Linux

The test program is started like this:

uml-22-241>/rhel5.x86_64/java/jdk1.6.0_23/bin/java -cp /tmp/ -Djava.compiler=NONE Test

Here's the small test program, repeated for convenience:

public class Test implements Runnable {
  int n;

  public Test(int i) {
    n = i;

  public static void main(String args[]) {
    for (int i = 0; i < 100; i++) {
      Thread t = new Thread(new Test(i));

  public void run() {
    long i = 0;
    while (true) {
      Test2 test = new Test2();
      if (i % 100000 == 0)

public class Test2 {
  float lf;

  public Test2() {
    this(11, 0.75f);

  public Test2(int x, float f) {
    if (f <= 0 || Float.isNaN(f))
      System.out.println(f + " < 0 ");
    this.lf = f;

Any help or suggestion about how to solve this problem is much appreciated!