Hello all, I wrote an application running under RedHat 5.1 and JDK1.1.7a1. It randomly causes core dump and file corruption with following message: ------ SIGSEGV 11* segmentation violation stackbase=0x4137a000, stackpointer=0x41379cac Full thread dump: "process reaper" (TID:0x4066f1b8, sys_thread_t:0x41669e0c, state:CW) prio=5 java.lang.Thread.run(Thread.java) "Screen Updater" (TID:0x40674da0, sys_thread_t:0x4168ae0c, state:CW) prio=4 java.lang.Object.wait(Object.java) sun.awt.ScreenUpdater.nextEntry(ScreenUpdater.java:70) sun.awt.ScreenUpdater.run(ScreenUpdater.java:90) "AWT-Finalizer" (TID:0x40675578, sys_thread_t:0x416abe0c, state:CW) prio=9 java.lang.Object.wait(Object.java) sun.awt.AWTFinalizer.run(AWTFinalizer.java:40) "TimerQueue" (TID:0x4066dc90, sys_thread_t:0x41648e0c, state:CW) prio=5 javax.swing.TimerQueue.run(TimerQueue.java:205) java.lang.Thread.run(Thread.java) "Thread-19" (TID:0x40665610, sys_thread_t:0x41627e0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-20" (TID:0x406656e0, sys_thread_t:0x41606e0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-17" (TID:0x40665408, sys_thread_t:0x415e5e0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-18" (TID:0x406653b0, sys_thread_t:0x415c4e0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-15" (TID:0x40665210, sys_thread_t:0x415a3e0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-16" (TID:0x406654a8, sys_thread_t:0x41582e0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-13" (TID:0x40665300, sys_thread_t:0x41561e0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-14" (TID:0x406652a8, sys_thread_t:0x41540e0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-11" (TID:0x406650f8, sys_thread_t:0x4151fe0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-12" (TID:0x406650a0, sys_thread_t:0x414fee0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-9" (TID:0x40664ef8, sys_thread_t:0x414dde0c, state:CW) prio=5 Nest.run(Nest.java:57) "Thread-10" (TID:0x40665190, sys_thread_t:0x414bce0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-7" (TID:0x40665028, sys_thread_t:0x4149be0c, state:CW) prio=5 SyncBuffer.get(SyncBuffer.java:53) Emmi.rcv(Emmi.java:131) Emmi.flex(Emmi.java:336) Nest.run(Nest.java:97) "Thread-8" (TID:0x40664f98, sys_thread_t:0x4147ae0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "Thread-5" (TID:0x40664e18, sys_thread_t:0x41459e0c, state:CW) prio=5 Nest.run(Nest.java:182) "Thread-6" (TID:0x40664db0, sys_thread_t:0x41438e0c, state:CW) prio=5 SerialInputStream.read(SerialInputStream.java:81) java.io.BufferedInputStream.fill(BufferedInputStream.java) java.io.BufferedInputStream.read(BufferedInputStream.java) RxReader.run(RxReader.java:20) "AWT-Motif" (TID:0x4065b568, sys_thread_t:0x41413e0c, state:CW) prio=5 java.lang.Thread.run(Thread.java) "AWT-Input" (TID:0x4065b2d0, sys_thread_t:0x413f2e0c, state:CW) prio=5 "AWT-EventQueue-0" (TID:0x4065b2e8, sys_thread_t:0x413d1e0c, state:CW) prio= 5 java.lang.Object.wait(Object.java) java.awt.EventQueue.getNextEvent(EventQueue.java:118) java.awt.EventDispatchThread.run(EventDispatchThread.java:67) "Finalizer thread" (TID:0x40656210, sys_thread_t:0x4139ae0c, state:CW) prio= 1 "Async Garbage Collector" (TID:0x40656258, sys_thread_t:0x41379e0c, state:R) prio=1 *current thread* "Idle thread" (TID:0x406562a0, sys_thread_t:0x41358e0c, state:R) prio=0 "Clock" (TID:0x40656088, sys_thread_t:0x41337e0c, state:CW) prio=12 "main" (TID:0x406560b0, sys_thread_t:0x81cde98, state:CW) prio=5 Monitor Cache Dump: <unknown key> (0x0x4151fe0c): <unowned> Waiting to be notified: "Thread-11" (0x4151fe0c) SyncBuffer@1080446880/1080963904: <unowned> Waiting to be notified: "Thread-7" (0x4149be0c) <unknown key> (0x0x414dde0c): <unowned> Waiting to be notified: "Thread-9" (0x414dde0c) java.io.BufferedInputStream@1080446968/1080959328: owner "Thread-8" (0x4147a e0c, 1 entry) <unknown key> (0x0x41459e0c): <unowned> Waiting to be notified: "Thread-5" (0x41459e0c) java.io.BufferedInputStream@1080447752/1080981072: owner "Thread-14" (0x4154 0e0c, 1 entry) java.io.BufferedInputStream@1080447232/1080975032: owner "Thread-12" (0x414f ee0c, 1 entry) java.io.BufferedInputStream@1080446720/1080968992: owner "Thread-10" (0x414b ce0c, 1 entry) sun.awt.ScreenUpdater@1080511904/1081248824: <unowned> Waiting to be notified: "Screen Updater" (0x4168ae0c) sun.awt.motif.MToolkit@1080406888/1080788368: <unowned> Waiting to be notified: "AWT-Motif" (0x41413e0c) java.awt.EventQueue@1080406840/1080788624: <unowned> Waiting to be notified: "AWT-EventQueue-0" (0x413d1e0c) <unknown key> (0x0x41627e0c): <unowned> Waiting to be notified: "Thread-19" (0x41627e0c) java.io.BufferedInputStream@1080446496/1080956672: owner "Thread-6" (0x41438 e0c, 1 entry) <unknown key> (0x0x415e5e0c): <unowned> Waiting to be notified: "Thread-17" (0x415e5e0c) java.io.BufferedInputStream@1080448536/1080999328: owner "Thread-20" (0x4160 6e0c, 1 entry) java.io.BufferedInputStream@1080447512/1080987112: owner "Thread-16" (0x4158 2e0c, 1 entry) java.io.BufferedInputStream@1080448016/1080993288: owner "Thread-18" (0x415c 4e0c, 1 entry) javax.swing.TimerQueue@1080482968/1081122528: <unowned> Waiting to be notified: "TimerQueue" (0x41648e0c) <unknown key> (0x0x415a3e0c): <unowned> Waiting to be notified: "Thread-15" (0x415a3e0c) sun.awt.AWTFinalizer@1080513912/1080660456: <unowned> Waiting to be notified: "AWT-Finalizer" (0x416abe0c) <unknown key> (0x0x41561e0c): <unowned> Waiting to be notified: "Thread-13" (0x41561e0c) Registered Monitor Dump: Thread queue lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry) Waiting to be notified: "main" (0x81cde98) Name and type hash table lock: <unowned> String intern lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry) JNI pinning lock: <unowned> JNI global reference lock: owner "Async Garbage Collector" (0x41379e0c, 1 en try) BinClass lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry) Class loading lock: <unowned> Java stack lock: <unowned> Code rewrite lock: <unowned> Heap lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry) Has finalization queue lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry) entry) Finalize me queue lock: owner "Async Garbage Collector" (0x41379e0c, 1 entry ) Waiting to be notified: "Finalizer thread" (0x4139ae0c) Dynamic loading lock: <unowned> Monitor IO lock: <unowned> Child death monitor: <unowned> Waiting to be notified: "process reaper" (0x41669e0c) Event monitor: <unowned> I/O monitor: <unowned> Waiting to be notified: "AWT-Input" (0x413f2e0c) Alarm monitor: <unowned> Waiting to be notified: "Clock" (0x41337e0c) Monitor registry: owner "Async Garbage Collector" (0x41379e0c, 1 entry) Thread Alarm Q: sys_thread_t 0x413f2e0c [Timeout expired] sys_thread_t 0x41648e0c [Timeout in 291 ms] sys_thread_t 0x41459e0c [Timeout in 639 ms] sys_thread_t 0x414dde0c [Timeout in 2238 ms] sys_thread_t 0x4151fe0c [Timeout in 2238 ms] sys_thread_t 0x415a3e0c [Timeout in 2238 ms] sys_thread_t 0x41627e0c [Timeout in 2238 ms] sys_thread_t 0x41561e0c [Timeout in 2308 ms] sys_thread_t 0x415e5e0c [Timeout in 2308 ms] sys_thread_t 0x4149be0c [Timeout in 29887 ms] гн- and when I run klock, it says as following, which it's a part of my data file. But after I reboot, the error's gone. klock: error in loading shared libraries /opt/kde/lib/libkdeui.so.1: undefined symbol: 00 00 00 00 00 00 @ seem 546:1 byte 00-03 = 03 30 18 81 @ seem 552:1 byte 00-00 = 00 @ seem 556:1 byte 00-00 = 02 @ seem 558:1 byte 00-00 = 00 @ seem 561:1 byte 00-01 = 00 b4 @ seem 563:1 byte 00-03 = 00 00 00 00 @ seem 564:1 byte 00-0d = 02 50 14 00 00 00 00 00 00 00 00 00 00 00 @ seem 569:1 byte 00-0f = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff @ seem 569:1 byte 10-1f = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff @ seem 569:1 byte 20-24 = ff ff ff ff ff END_GROUP EXIT Please could anyone help? Best regards, Howard