Exception in a gwt program [closed]

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an exception in gwt program

java.lang.ExceptionInInitializerError

[ERROR] Unable to bind socket on port 9997 -- is another session active?
java.net.BindException: Address already in use
    at java.net.PlainSocketImpl.socketBind(Native Method)
    at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:365)
    at java.net.ServerSocket.bind(ServerSocket.java:319)
    at java.net.ServerSocket.bind(ServerSocket.java:277)
    at com.google.gwt.dev.shell.BrowserListener.<init>(BrowserListener.java:67)
    at com.google.gwt.dev.DevModeBase.ensureCodeServerListener(DevModeBase.java:898)
    at com.google.gwt.dev.DevModeBase.doStartup(DevModeBase.java:888)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1030)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:783)
    at com.google.gwt.dev.DevMode.main(DevMode.java:275)
log4j:WARN No appenders could be found for logger (org.apache.jasper.compiler.JspRuntimeContext).
log4j:WARN Please initialize the log4j system properly.
Starting Jetty on port 8888
   [WARN] failed SelectChannelConnector@127.0.0.1:8888
java.net.BindException: Address already in use
    at sun.nio.ch.Net.bind(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:119)
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:59)
    at org.mortbay.jetty.nio.SelectChannelConnector.open(SelectChannelConnector.java:205)
    at org.mortbay.jetty.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:304)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:39)
    at org.mortbay.jetty.Server.doStart(Server.java:233)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:39)
    at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:543)
    at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:421)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1035)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:783)
    at com.google.gwt.dev.DevMode.main(DevMode.java:275)
   [WARN] failed Server@69d02b
java.net.BindException: Address already in use
    at sun.nio.ch.Net.bind(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:119)
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.开发者_如何学Cjava:59)
    at org.mortbay.jetty.nio.SelectChannelConnector.open(SelectChannelConnector.java:205)
    at org.mortbay.jetty.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:304)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:39)
    at org.mortbay.jetty.Server.doStart(Server.java:233)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:39)
    at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:543)
    at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:421)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1035)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:783)
    at com.google.gwt.dev.DevMode.main(DevMode.java:275)
Port 127.0.0.1:8888 is already is use; you probably still have another session active

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here's what helped me : http://isurprise.mobi/live/error-port-127-0-0-18888-is-already-in-use

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You have another session active, the stack trace is pretty obvious:

[ERROR] Unable to bind socket on port 9997 -- is another session active?

java.net.BindException: Address already in use at java.net.PlainSocketImpl.socketBind(Native Method)

Port 127.0.0.1:8888 is already is use; you probably still have another session active

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You haven't provided enough information, such as the stack trace and the code. However, what I can tell is that ExceptionInInitializerError occurs when a static initialization code throws a runtime exception. Note that the exception wraps the triggering runtime exception, so try to view the complete stack trace and analyze it.

Here is an example:

public class Test {
    static {
        String s = "hi";
        s.substring(10);
    }

    public static void main(String[] args) {

    }
}

The stack trace printout is:

java.lang.ExceptionInInitializerError
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -8
    at java.lang.String.substring(String.java:1938)
    at java.lang.String.substring(String.java:1905)
    at Test.<clinit>(Test.java:5)
Exception in thread "main" 

--EDIT--

now that you provided more details, take a look at the other response which is more specific to your case: you either have another session of your GWT application already running, or you have some other server application on the localhost, listening on port 8888.

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This thread might be of help to you.

Quoting the top answer from that thread:

"Even after you have exited all browser connections, the code server is still running waiting for new connections. You need to stop that connection from your previous launch before starting another one. Also, note that you don't necessarily have to restart it at all -- just make your changes and refresh the browser or launch a new browser."

From my personal experience , try launching the webapp after 1 min or so. This problem would go away. Not a clean way to do stuffs and so there is a bug filed with the GWT team for this case.