[re] Java executables can abort trying to access a null pointer in a leaf function

Wed Feb 1 22:02:00 GMT 2006

tsuraan wrote:
> In April, 2000, the following code was posted to the java-gnats at
> cygnus mailing list as a piece of code that causes a gcj compiled
> program to abort rather than printing out the NullPointerException and
> exiting:
>> public class NullPointer
> {
> private int i = 5;
>> public static void main(String[] args)
> {
> try
> {
> new NullPointer().foo(null);
> }
> catch (NullPointerException x)
> {
> System.out.println(x);
> }
> }
>> void foo(NullPointer e)
> {
> e.i += 4;
> };
> }
>> I'm getting the same result (program exit with abort) using
> gcc-4.1-20051029 under FreeBSD 5.4. This happens reliably on many
> machines.

Does this thing use DWARF based exception handling?
If so my guess would be a problem with MAKE_THROW_FRAME on this platfrom.
If making the first statement of foo something other than dereferencing 
the null pointer (like increment a static int) fixes the problem then I 
would be even more confident about this.
David Daney.