内存泄漏异常

Question

谁能帮我解决这个例外：

Jul 23, 2012 11:00:57 AM org.apache.catalina.loader.WebappClassLoader loadClass
INFO: Illegal access: this web application instance has been stopped already.  Could not load com.mchange.v2.sql.SqlUtils.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1597)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:531)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142)
    at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85)
    at net.customware.gwt.dispatch.server.AbstractDispatch.doExecute(AbstractDispatch.java:81)
    at net.customware.gwt.dispatch.server.AbstractDispatch.execute(AbstractDispatch.java:68)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:216)
    at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:141)
    at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:93)
    at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:63)
    at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:122)
    at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:110)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

并且还为它提供了可能的解决方案..？

提前谢谢...

Answer 1

基本问题是tomcat为每个webapp创建一个新的ClassLoader，并在你重置应用程序时禁用类加载器，例如通过热部署新版本。 c3p0 创建辅助线程。如果 c3p0 已在 web 应用程序的类加载器中加载，然后应用程序被重置，c3p0 的线程可能仍处于活动状态并持有对从现已失效的 ClassLoader 加载的对象的引用，从而导致您在必须使用新类时看到的那种错误已加载。

多线程组件和 tomcat 的“热”类加载方案之间的交互可能具有挑战性。一些建议：

1) 如果您的 Web 应用构建了自己的 c3p0 数据源（例如在 ContextListener 中），请确保在应用关闭时（在同一个 ContextListener 中）也关闭（）数据源

2) 尝试将 c3p0 和您的 JDBC 驱动程序类加载到 Web 应用特定 ClassLoader 之外的其他东西中。将 c3p0 jar 文件、change-commons-java jar 文件和 JDBC 驱动程序 jar 文件放在 common、system 或 bootstrap ClassLoader 可以找到它的位置。确保将这些文件从您的 web 应用程序的 lib 目录中取出，因为首先尝试了 web 应用程序 ClassLoader。请参阅http://tomcat.apache.org/tomcat-6.0-doc/class-loader-howto.html 了解更多信息。

我希望这会有所帮助！