I didn’t notice it until today during some testing locally on my pc, that Tomcat had posted an error in the log file. I’m using Tomcat 6.0.29 and Java JDK 1.6.
Dec 1, 2010 12:36:57 pm org.apache.catalina.core.StandardContext reload
INFO: Reloading this Context has started
Dec 1, 2010 12:36:57 pm org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVER: The web application [/AutoSpyder] appears to have started a thread named
[AWT-Windows] but has failed to stop it. This is very likely to create a memory
leak.
What? I’ve never seen this before. So I checked my log file from yesterday, and sure enough, this error was there too. I don’t quite understand what’s causing this.
Can I assume that it would have to be one of my servlets that uses objects from the java.awt package? If so, how do I pinpoint the code that is causing this?
Edited to add Thread Dump
2010-12-01 14:28:18
Full thread dump Java HotSpot(TM) Client VM (17.1-b03 mixed mode, sharing):
"JMX server connection timeout 34" daemon prio=6 tid=0x03069400 nid=0x960 in Object.wait() [0x0461f000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a [I)
at com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout.run(ServerCommunicatorAdmin.java:150)
- locked (a [I)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"RMI Scheduler(0)" daemon prio=6 tid=0x03069000 nid=0xe88 waiting on condition [0x045cf000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
at java.util.concurrent.DelayQueue.take(DelayQueue.java:164)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:609)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:602)
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"RMI TCP Connection(1)-192.168.0.102" daemon prio=6 tid=0x0308a400 nid=0xebc runnable [0x0457f000]
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
- locked (a java.io.BufferedInputStream)
at java.io.FilterInputStream.read(FilterInputStream.java:66)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:517)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
"RMI TCP Accept-0" daemon prio=6 tid=0x039e0c00 nid=0xc68 runnable [0x0452f000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:390)
- locked (a java.net.SocksSocketImpl)
at java.net.ServerSocket.implAccept(ServerSocket.java:453)
at java.net.ServerSocket.accept(ServerSocket.java:421)
at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(LocalRMIServerSocketFactory.java:34)
at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.executeAcceptLoop(TCPTransport.java:369)
at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.run(TCPTransport.java:341)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"AWT-Windows" daemon prio=6 tid=0x02b65400 nid=0x7c4 runnable [0x042cf000]
java.lang.Thread.State: RUNNABLE
at sun.awt.windows.WToolkit.eventLoop(Native Method)
at sun.awt.windows.WToolkit.run(WToolkit.java:293)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"Java2D Disposer" daemon prio=10 tid=0x02fccc00 nid=0x93c in Object.wait() [0x039df000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
- locked (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
at sun.java2d.Disposer.run(Disposer.java:127)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-6" daemon prio=6 tid=0x03322800 nid=0xfec in Object.wait() [0x0395f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-5" daemon prio=6 tid=0x02ba5c00 nid=0xdbc in Object.wait() [0x0390f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-4" daemon prio=6 tid=0x02ff6400 nid=0xa1c in Object.wait() [0x038bf000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-3" daemon prio=6 tid=0x0317e400 nid=0x850 in Object.wait() [0x0386f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-2" daemon prio=6 tid=0x03314800 nid=0xf9c in Object.wait() [0x0381f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-1" daemon prio=6 tid=0x02efe800 nid=0x250 in Object.wait() [0x037cf000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
- locked (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"TP-Monitor" daemon prio=6 tid=0x02eed800 nid=0xd64 in Object.wait() [0x0375f000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)
at org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable.run(ThreadPool.java:565)
- locked (a org.apache.tomcat.util.threads.ThreadPool$MonitorRunnable)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"TP-Processor4" daemon prio=6 tid=0x0318b000 nid=0x998 runnable [0x0370f000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:390)
- locked (a java.net.SocksSocketImpl)
at java.net.ServerSocket.implAccept(ServerSocket.java:453)
at java.net.ServerSocket.accept(ServerSocket.java:421)
at org.apache.jk.common.ChannelSocket.accept(ChannelSocket.java:312)
at org.apache.jk.common.ChannelSocket.acceptConnections(ChannelSocket.java:666)
at org.apache.jk.common.ChannelSocket$SocketAcceptor.runIt(ChannelSocket.java:877)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"TP-Processor3" daemon prio=6 tid=0x0308f800 nid=0x92c in Object.wait() [0x036bf000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:662)
- locked (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"TP-Processor2" daemon prio=6 tid=0x03192400 nid=0xfac in Object.wait() [0x0366f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:662)
- locked (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"TP-Processor1" daemon prio=6 tid=0x03182400 nid=0x8d8 in Object.wait() [0x0361f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Object.wait(Object.java:485)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:662)
- locked (a org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"http-8080-Acceptor-0" daemon prio=6 tid=0x03172400 nid=0xf04 runnable [0x035cf000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:390)
- locked (a java.net.SocksSocketImpl)
at java.net.ServerSocket.implAccept(ServerSocket.java:453)
at java.net.ServerSocket.accept(ServerSocket.java:421)
at org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:61)
at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:352)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"ContainerBackgroundProcessor[StandardEngine[Catalina]]" daemon prio=6 tid=0x03163400 nid=0xbe8 waiting on condition [0x0357f000]
java.lang.Thread.State: TIMED_WAITING (sleeping)
at java.lang.Thread.sleep(Native Method)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1579)
at java.lang.Thread.run(Thread.java:662)
Locked ownable synchronizers:
- None
"GC Daemon" daemon prio=2 tid=0x0307bc00 nid=0x110 in Object.wait() [0x0349f000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a sun.misc.GC$LatencyLock)
at sun.misc.GC$Daemon.run(GC.java:100)
- locked (a sun.misc.GC$LatencyLock)
Locked ownable synchronizers:
- None
"Low Memory Detector" daemon prio=6 tid=0x02aecc00 nid=0x5b4 runnable [0x00000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"CompilerThread0" daemon prio=10 tid=0x02ae7000 nid=0x798 waiting on condition [0x00000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Attach Listener" daemon prio=10 tid=0x02ae5800 nid=0xddc waiting on condition [0x00000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Signal Dispatcher" daemon prio=10 tid=0x02ae4000 nid=0xc00 runnable [0x00000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"Finalizer" daemon prio=8 tid=0x02add400 nid=0x378 in Object.wait() [0x02caf000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
- locked (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)
Locked ownable synchronizers:
- None
"Reference Handler" daemon prio=10 tid=0x02adbc00 nid=0x474 in Object.wait() [0x02c5f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:485)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
- locked (a java.lang.ref.Reference$Lock)
Locked ownable synchronizers:
- None
"main" prio=6 tid=0x002b7000 nid=0x14c runnable [0x0090f000]
java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:390)
- locked (a java.net.SocksSocketImpl)
at java.net.ServerSocket.implAccept(ServerSocket.java:453)
at java.net.ServerSocket.accept(ServerSocket.java:421)
at org.apache.catalina.core.StandardServer.await(StandardServer.java:389)
at org.apache.catalina.startup.Catalina.await(Catalina.java:662)
at org.apache.catalina.startup.Catalina.start(Catalina.java:614)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Locked ownable synchronizers:
- None
"VM Thread" prio=10 tid=0x02ada400 nid=0x210 runnable
"VM Periodic Task Thread" prio=10 tid=0x02aefc00 nid=0x79c waiting on condition
JNI global references: 1529
Try taking a thread dump to get a list of all the threads running on your server. From this, you may be able to pinpoint exactly which class started the thread based on the stack traces
Windows
on the console window press
ctrl + breakUnix
in a command line enter:
kill -3 <pid>