Reproducible steps:
1. start java harness
/usr/java/bin/java -verify javasoft.sqe.harness.Main awt_flora.jtp
(File attached)
2. click Start button twice
3. click "OK" in "Harness already running" message box popup.

Note: This procedure is not 100% reproducible, user sometimes have to repeat
step 2. followed by step 3. couple of times to get core dumped.
I managed to reproduce this core dump in both Solaris x86 and ultra-sparc within
1 to 5 minutes each.
Host flora is Solaris 2.6 x86 dual CPU machine.
Host santana is Solaris 2.5.1 ultra2 dual CPU machine.
If core file will help you to diagnose this problem, please contact me to get it.

flora% /usr/java/bin/java -fullversion
java full version "JDK1.1.5K"

flora% SIGSEGV 11* segmentation violation
    si_signo [11]: SIGSEGV 11* segmentation violation
    si_errno [0]: Error 0
    si_code [1]: SEGV_MAPERR [addr: 0x8]

        stackbase=DEA19000, stackpointer=DEA18B34

Full thread dump:
    "AWT-Dispatch-Proxy" (TID:0xdef26c68, sys_thread_t:0xdea18d84, state:R) prio=5
 *current thread*
        sun.awt.motif.X11Graphics.<init>(X11Graphics.java:66)
        sun.awt.motif.MComponentPeer.getGraphics(MComponentPeer.java:192)
        java.awt.Component.getGraphics(Component.java:1160)
        java.awt.Component.dispatchEventImpl(Component.java:1716)
        java.awt.Component.dispatchEvent(Component.java:1704)
        java.awt.EventDispatchThread.run(EventDispatchThread.java:63)
    "HarnessWorker" (TID:0xdef0c408, sys_thread_t:0xdea3ad84, state:R) prio=3
        java.io.FileInputStream.read(FileInputStream.java)
        java.io.BufferedInputStream.fill(BufferedInputStream.java)
        java.io.BufferedInputStream.read(BufferedInputStream.java)
        javasoft.sqe.harness.TestFinder.nextCh(TestFinder.java:230)
        javasoft.sqe.harness.TestFinder.scan(TestFinder.java:261)
        javasoft.sqe.harness.TestFinder.more(TestFinder.java:141)
        javasoft.sqe.harness.TestFinder.next(TestFinder.java:161)
        javasoft.sqe.harness.TestRunner.readAheadTests(TestRunner.java:59)
        javasoft.sqe.harness.Harness.run(Harness.java:418)
        javasoft.sqe.harness.Harness.workerCallback(Harness.java:326)
        javasoft.sqe.harness.HarnessWorker.run(Harness.java:921)
    "AWT-Finalizer" (TID:0xdef0e700, sys_thread_t:0xdea5cd84, state:CW) prio=9
        java.lang.Object.wait(Object.java)
        sun.awt.AWTFinalizer.run(AWTFinalizer.java:48)
    "Screen Updater" (TID:0xdef0a328, sys_thread_t:0xdea7ed84, state:CW) prio=4
        java.lang.Object.wait(Object.java)
        sun.awt.ScreenUpdater.nextEntry(ScreenUpdater.java:78)
        sun.awt.ScreenUpdater.run(ScreenUpdater.java:98)
    "AWT-Motif" (TID:0xdef06868, sys_thread_t:0xdeaa0d84, state:MW) prio=5
        java.lang.Thread.run(Thread.java)
    "AWT-Input" (TID:0xdef06888, sys_thread_t:0xdeac2d84, state:MW) prio=5
    "AWT-EventQueue-0" (TID:0xdef068a0, sys_thread_t:0xdfc29d84, state:MW) prio=5
        java.awt.Component.dispatchEventImpl(Component.java:1817)
        java.awt.Component.dispatchEvent(Component.java:1704)
        java.awt.EventDispatchThread.run(EventDispatchThread.java:63)
    "Finalizer thread" (TID:0xdef00178, sys_thread_t:0xdfcffd84, state:CW) prio=1
    "Async Garbage Collector" (TID:0xdef001c0, sys_thread_t:0xdfd21d84, state:CW)
prio=1
    "Idle thread" (TID:0xdef00208, sys_thread_t:0xdfd43d84, state:R) prio=0
    "Clock" (TID:0xdef00048, sys_thread_t:0xdfd65d84, state:CW) prio=12
    "main" (TID:0xdef00078, sys_thread_t:0x8063168, state:CW) prio=5
Monitor Cache Dump:
    sun.awt.AWTFinalizer@DEF0E700/DEFB9410: <unowned>
        Waiting to be notified:
            "AWT-Finalizer" (0xdea5cd84)
    <unknown key> (0xdfd21d84): <unowned>
        Waiting to be notified:
            "Async Garbage Collector" (0xdfd21d84)
    sun.awt.ScreenUpdater@DEF0A328/DEF96D68: <unowned>
        Waiting to be notified:
            "Screen Updater" (0xdea7ed84)
    javasoft.sqe.harness.TestFinder@DEF20938/DF062178: owner "HarnessWorker" (0xde
a3ad84, 2 entries)
    <unknown key> (0xdfe864b8): owner "AWT-Dispatch-Proxy" (0xdea18d84, 1 entry)
    sun.awt.motif.MToolkit@DEF06670/DEF56938: owner "AWT-Dispatch-Proxy" (0xdea18d
84, 1 entry)
        Waiting to enter:
            "AWT-Input" (0xdeac2d84)
            "AWT-Motif" (0xdeaa0d84)
            "AWT-EventQueue-0" (0xdfc29d84)
    java.io.BufferedInputStream@DEF2B0B0/DF0B4F50: owner "HarnessWorker" (0xdea3ad
84, 1 entry)
Registered Monitor Dump:
    Thread queue lock: <unowned>
        Waiting to be notified:
            "main" (0x8063168)
    Verifier lock: <unowned>
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
        Waiting to be notified:
            "Finalizer thread" (0xdfcffd84)
    Monitor IO lock: <unowned>
    Child death monitor: <unowned>
    Event monitor: <unowned>
    I/O monitor: <unowned>
    Alarm monitor: <unowned>
        Waiting to be notified:
            "Clock" (0xdfd65d84)
    Sbrk lock: <unowned>
    Monitor registry: owner "AWT-Dispatch-Proxy" (0xdea18d84, 1 entry)
Thread Alarm Q:
    sys_thread_t 0xdfd21d84 [Timeout in 595 ms]
Abort (core dumped)
-------------------------------------------------------------------------------
santana% /usr/java/bin/java -fullversion
java full version "JDK1.1.5K"

santana% ./runinteractive.csh
SIGSEGV 11* segmentation violation
    si_signo [11]: SIGSEGV 11* segmentation violation
    si_errno [0]: Error 0
    si_code [1]: SEGV_MAPERR [addr: 0x574fb8]

        stackbase=EE012000, stackpointer=EE011748

Full thread dump:
    "HarnessWorker" (TID:0xee70e3f8, sys_thread_t:0xedf21db8, state:R) prio=3
        java.io.FileInputStream.<init>(FileInputStream.java)
        sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java
:150)
        sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnecti
on.java:170)
        java.net.URL.openStream(URL.java)
        javasoft.sqe.harness.TestFinder.scan(TestFinder.java:259)
        javasoft.sqe.harness.TestFinder.more(TestFinder.java:141)
        javasoft.sqe.harness.TestFinder.next(TestFinder.java:161)
        javasoft.sqe.harness.TestRunner.readAheadTests(TestRunner.java:59)
        javasoft.sqe.harness.Harness.run(Harness.java:418)
        javasoft.sqe.harness.Harness.workerCallback(Harness.java:326)
        javasoft.sqe.harness.HarnessWorker.run(Harness.java:921)
    "AWT-Finalizer" (TID:0xee70ed18, sys_thread_t:0xedf51db8, state:CW) prio=9
        java.lang.Object.wait(Object.java)
        sun.awt.AWTFinalizer.run(AWTFinalizer.java:48)
    "Screen Updater" (TID:0xee70a6a0, sys_thread_t:0xedf81db8, state:CW) prio=4
        java.lang.Object.wait(Object.java)
        sun.awt.ScreenUpdater.nextEntry(ScreenUpdater.java:78)
        sun.awt.ScreenUpdater.run(ScreenUpdater.java:98)
    "AWT-Motif" (TID:0xee706930, sys_thread_t:0xedfb1db8, state:CW) prio=5
        java.lang.Thread.run(Thread.java)
    "AWT-Input" (TID:0xee706888, sys_thread_t:0xedfe1db8, state:R) prio=5
    "AWT-EventQueue-0" (TID:0xee7068a0, sys_thread_t:0xee011db8, state:R) prio=5 *
current thread*
        sun.awt.motif.X11Graphics.setColor(X11Graphics.java:144)
        sun.awt.motif.MComponentPeer.getGraphics(MComponentPeer.java:193)
        java.awt.Component.getGraphics(Component.java:1160)
        java.awt.Component.dispatchEventImpl(Component.java:1716)
        java.awt.Component.dispatchEvent(Component.java:1704)
        java.awt.EventDispatchThread.run(EventDispatchThread.java:63)
    "Finalizer thread" (TID:0xee700178, sys_thread_t:0xee2c1db8, state:R) prio=1
    "Async Garbage Collector" (TID:0xee7001c0, sys_thread_t:0xee2f1db8, state:R) p
rio=1
    "Idle thread" (TID:0xee700208, sys_thread_t:0xee3c1db8, state:R) prio=0
    "Clock" (TID:0xee700048, sys_thread_t:0xee3f1db8, state:CW) prio=12
    "main" (TID:0xee700078, sys_thread_t:0x3a088, state:CW) prio=5
Monitor Cache Dump:
    javasoft.sqe.harness.TestFinder@EE7106F8/EE7DC260: owner "HarnessWorker" (0xed
f21db8, 2 entries)
    sun.awt.AWTFinalizer@EE70ED18/EE7B9460: <unowned>
        Waiting to be notified:
            "AWT-Finalizer" (0xedf51db8)
    www.protocol.file.FileURLConnection@EE72CC38'>sun.net.www.protocol.file.FileURLConnection@EE72CC38/EE8B88D0: owner "HarnessW
orker" (0xedf21db8, 1 entry)
    <unknown key> (0xee2f1db8): owner "Async Garbage Collector" (0xee2f1db8, 1 ent
ry)
    <unknown key> (0xef513bb0): owner "AWT-EventQueue-0" (0xee011db8, 1 entry)
    sun.awt.motif.MToolkit@EE706670/EE7568E0: owner "AWT-EventQueue-0" (0xee011db8
, 1 entry)
        Waiting to be notified:
            "AWT-Motif" (0xedfb1db8)
    sun.awt.ScreenUpdater@EE70A6A0/EE77A850: <unowned>
        Waiting to be notified:
            "Screen Updater" (0xedf81db8)
Registered Monitor Dump:
    Thread queue lock: <unowned>
        Waiting to be notified:
            "main" (0x3a088)
    Verifier lock: <unowned>
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
    Monitor IO lock: owner "HarnessWorker" (0xedf21db8, 1 entry)
    Child death monitor: <unowned>
    Event monitor: <unowned>
    I/O monitor: owner "AWT-Input" (0xedfe1db8, 1 entry)
    Alarm monitor: <unowned>
        Waiting to be notified:
            "Clock" (0xee3f1db8)
    Sbrk lock: <unowned>
    Monitor registry: owner "AWT-EventQueue-0" (0xee011db8, 1 entry)
Thread Alarm Q:
    sys_thread_t 0xedfb1db8 [Timeout in 65 ms]
    sys_thread_t 0xedfe1db8 [Timeout in 221 ms]
Abort (core dumped)