javaSE小问题？

Question

写了一个服务端和客户端发信息的小程序。真是搞不懂，有的时候运行完全没问题，可是有的时候出现这个问题：
java.net.ConnectException: Connection timed out: connect
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:519)
        at java.net.Socket.connect(Socket.java:469)
        at java.net.Socket.<init>(Socket.java:366)
        at java.net.Socket.<init>(Socket.java:180)
        at com.zhaohailiang.ChatClient.connect(ChatClient.java:50)
        at com.zhaohailiang.ChatClient.launchFrame(ChatClient.java:41)
        at com.zhaohailiang.QQEnter$QQEnterEvent.actionPerformed(QQEnter.java:162)
        at java.awt.Button.processActionEvent(Button.java:392)
        at java.awt.Button.processEvent(Button.java:360)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at com.zhaohailiang.ChatClient$tfListener.actionPerformed(ChatClient.java:79)
        at java.awt.TextField.processActionEvent(TextField.java:596)
        at java.awt.TextField.processEvent(TextField.java:564)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
跪求高手解疑。。

Answer 1

连接超时，有可能是用户多了以后连接不上了，有个maxThreads参数，指定最多同时有多少个线程，你可以把这个参数调大点

Answer 2

我知道什么原因了,.你一定是首先启动了客户端,,然后客户端不停的寻找服务器端,,,因为你服务器端并没有运行起来,所以,,客户端就抛一个连接超时的错误而有时候你先启动了服务器端,所以没有任何错误来我的Java群吧:  JAVAMM工作室   49167765每个星期都有一节基础课讲解

Answer 3

LZ一定要去看看，全部是MM的JAVA工作室，