解决Tomcat奇怪的问题：java.net.SocketException: Too many open files

Tomcat运行一段时间后自动当掉，察看日志：java.net.SocketException: Too many open files?严重: Endpoint ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=80] ignored exception: java.net.SocketException: Too many open files
java.net.SocketException: Too many open files
?at java.net.PlainSocketImpl.socketAccept(Native Method)
?at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:384)
?at java.net.ServerSocket.implAccept(ServerSocket.java:450)
?at java.net.ServerSocket.accept(ServerSocket.java:421)
?at org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:60)
?at org.apache.tomcat.util.net.PoolTcpEndpoint.acceptSocket(PoolTcpEndpoint.java:407)
?at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:70)
?at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
?at java.lang.Thread.run(Thread.java:595)??这个错误，通过增大系统的max open file 可以得到改善，参考：http://kbase.redhat.com/faq/FAQ_80_1540.shtm?设置 max open file 为更大以后，没有了这个错误。但是还存在一个错误：Exception Processing ErrorPage[errorCode=404, location=/error/error404.jsp]?
错误描述和解决办法如下面引用的一样：/****************************************/From :?http://www.jboss.org/index.html?module=bb&op=viewtopic&p=3840241