JVM got crashed

This is a java program including JNI native method. When program started, JVM got crashed and produced system core file. It seems the error was thrown from JNI. I am not familiar how to debug core file. Not sure what error can cause this problem. Anyone can help how to debug?
I used dbx tool to analyze the core file and got this:
pthdb_session.c, 833: 0 PTHDB_INTERNAL (internal error)
pthreaded.c, 1953: PTHDB_INTERNAL (internal error)

IOT/Abort trap in _p_sigsuspend at 0xd01246f4
[untrusted: /usr/lib/libpthreads.a(shr_xpg5.o)]
0xd01246f4 (_p_sigsuspend+0x94) 38210050 addi r1,0x50(r1)
(dbx) where
pthdb_session.c, 833: 0 PTHDB_INTERNAL (internal error)
pthreaded.c, 1953: PTHDB_INTERNAL (internal error)
_p_sigsuspend(??) at 0xd01246f4 [untrusted: /usr/lib/libpthreads.a(shr_xpg5.o)]
_p_sigtimedwait(??, ??, ??) at 0xd0124164 [untrusted: /usr/lib/libpthreads.a(shr_xpg5.o)]
reorder(0xd1cf136c, 0x330402c0, 0x3303f980, 0xf089a0bc, 0xd036aa94) at 0xd036ac90 [untrusted: /usr/lib/libc.a(shr.o)]
conv_time(??, ??, ??, ??, ??, ??) at 0xd03cead8 [untrusted: /usr/lib/libc.a(shr.o)]
.() at 0x0
doSystemDump() at 0xd1d46ca4
protectedDumpFunction() at 0xd1d47340
j9sig_protect() at 0xd1cef4c4
runDumpFunction() at 0xd1d4880c
triggerDumpAgents_26_24() at 0xd1d50a20
dumpCrashData() at 0xd1c9bf04
j9sig_protect() at 0xd1cef4c4
structuredSignalHandler() at 0xd1c9c1f4
masterSynchSignalHandler() at 0xd1cef718
pushArguments() at 0xd1c97a40
runCallInMethod(), line 608 in "jstartup.s"
gpProtectedRunCallInMethod() at 0xd1c96cf4
signalProtectAndRunGlue() at 0xd1c95af4
j9sig_protect() at 0xd1cef4c4
gpProtectAndRun() at 0xd1c97118
gpCheckCallin() at 0xd1c98018
callVirtualVoidMethodV() at 0xd1cac090
openClientConnection__10NICIClientF13NI_COMPONENTS(0x32913900, 0x304d6b68) at 0xd1a5b368 [untrusted: /essni/lib/libniciClient.a]
niCI.int.__srterm__1__Fv() at 0xd1a5a33c [untrusted: /essni/lib/libniciClient.a]