Need help isolating severe Tomcat v4.1.18 bug

[Kristján Bjarni Guðmundsson <kr...@hugvit.is>]

Specs and variables:
Windows NT 4 SP 6 
Tomcat v4.1.18 
JDK v1.4.0_02
CATALINA_OPTS=-Xms128M -Xmx1024M 

At random intervals I get this error on console, it seems that the socket 
for port 80 is
suddenly closed and the server stops responding.
What steps can I take to get more information about why this error is 
occuring? 

SEVERE: Endpoint ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=80] 
ignored 
exception: java.net.SocketException: socket closed 
java.net.SocketException: socket closed 
        at java.net.PlainSocketImpl.socketAccept(Native Method) 
        at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:353) 
        at java.net.ServerSocket.implAccept(ServerSocket.java:439) 
        at java.net.ServerSocket.accept(ServerSocket.java:410) 
        at 
org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(De 
faultServerSocketFactory.java:107) 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.acceptSocket(PoolTcpEndpoi 
nt.java:341) 
        at 
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java 
:497) 
        at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP 
ool.java:530) 
        at java.lang.Thread.run(Thread.java:536) 
8.1.2003 03:36:47 org.apache.tomcat.util.log.CommonLogHandler log 
SEVERE: Endpoint null shutdown due to exception: java.net.SocketException: 
Opera 
tion now in progress: create 
java.net.SocketException: Operation now in progress: create 
        at java.net.ServerSocket.createImpl(ServerSocket.java:245) 
        at java.net.ServerSocket.getImpl(ServerSocket.java:203) 
        at java.net.ServerSocket.bind(ServerSocket.java:309) 
        at java.net.ServerSocket.<init>(ServerSocket.java:183) 
        at java.net.ServerSocket.<init>(ServerSocket.java:139) 
        at 
org.apache.tomcat.util.net.DefaultServerSocketFactory.createSocket(De 
faultServerSocketFactory.java:96) 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.acceptSocket(PoolTcpEndpoi 
nt.java:389) 
        at 
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java 
:497) 
        at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP 
ool.java:530) 
        at java.lang.Thread.run(Thread.java:536) 
8.1.2003 03:36:47 org.apache.tomcat.util.log.CommonLogHandler log 
SEVERE: Caught exception trying to unlock accept. 
java.net.SocketException: Operation now in progress: create 
        at java.net.Socket.createImpl(Socket.java:313) 
        at java.net.Socket.<init>(Socket.java:286) 
        at java.net.Socket.<init>(Socket.java:119) 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.stopEndpoint(PoolTcpEndpoi 
nt.java:309) 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.acceptSocket(PoolTcpEndpoi 
nt.java:400) 
        at 
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java 
:497) 
        at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP 
ool.java:530) 
        at java.lang.Thread.run(Thread.java:536) 
8.1.2003 03:36:47 org.apache.tomcat.util.log.CommonLogHandler log 
SEVERE: Caught exception trying to close socket. 
java.lang.NullPointerException 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.stopEndpoint(PoolTcpEndpoi 
nt.java:321) 
        at 
org.apache.tomcat.util.net.PoolTcpEndpoint.acceptSocket(PoolTcpEndpoi 
nt.java:400) 
        at 
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java 
:497) 
        at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP 
ool.java:530) 
        at java.lang.Thread.run(Thread.java:536)