I have been working integrating PHP with Java 2 SE (1.3.1).  I have found that if a "complex" object is returned by another Java method call (as in a static Java method), the php code will core dump.  The problem appears to be related to the zend hashing code.  When the 'new' function is invoked on a Java object, it is hashed by zend for de-referencing.  However, if a java object is returned, no entry is made in the hash for that object, dereferencing said object causes zend to core.

Here's the GDB trace:

Program received signal SIGSEGV, Segmentation fault.
0x0 in ?? ()
(gdb) bt
#0  0x0 in ?? ()
#1  0xb6c18 in zend_hash_find (ht=0xfe23354c, 
    arKey=0x34d038 "adddescription", nKeyLength=15, pData=0xffbee6c0)
    at zend_hash.c:854
#2  0xe670c in execute ()
#3  0xb2cb4 in zend_execute_scripts (type=8, file_count=3) at zend.c:729
#4  0x365c4 in php_execute_script (primary_file=0xffbef938) at main.c:1221
#5  0x34400 in main (argc=2, argv=0xffbef9c4) at cgi_main.c:738


Here's my version info:
SunOS arcturus 5.7 Generic_106541-11 sun4u sparc SUNW,Ultra-1

java version "1.3.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0_02)
Java HotSpot(TM) Client VM (build 1.3.0_02, mixed mode)