java - GWT:计时器导致运行时警告

Question

我正在为学校作业开发我的第一个基于 GWT 的 Java 项目。它是一个聊天应用程序，客户端轮询服务器以获取新事件，而服务器则为每个用户保留一个计时器以检测不活动情况。

运行时出现以下问题:

Dec 8, 2009 7:41:17 PM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: /GAEChat/chat
java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)
    at java.security.AccessControlContext.checkPermission(Unknown Source)
    at java.security.AccessController.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPermission(Unknown Source)
    at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:151)
    at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkAccess(DevAppServerFactory.java:176)
    at java.lang.ThreadGroup.checkAccess(Unknown Source)
    at java.lang.Thread.init(Unknown Source)
    at java.lang.Thread.<init>(Unknown Source)
    at java.util.TimerThread.<init>(Unknown Source)
    at java.util.Timer.<init>(Unknown Source)
    at java.util.Timer.<init>(Unknown Source)
    at gaechat.server.ChatServiceImpl.<init>(ChatServiceImpl.java:22)
    at sun.reflect.GeneratedConstructorAccessor14.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.lang.Class.newInstance0(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:463)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:121)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
    at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:352)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
    at org.mortbay.jetty.Server.handle(Server.java:313)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:844)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)
    at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:442)

Here's the code repository 。问题似乎出在 server/ChatServiceImpl.java 中。

我做错了什么吗？我被困住了。

Answer 1

由于这是一项学校作业，请尝试先禁用 SecurityManager。

更新:除非您在某处设置了-Djava.security.manager，否则应该禁用它。 请参阅How to disable Java security manager?

顺便说一句，您可能对 this 感兴趣链接 ;) 该页面有可供下载的源代码。