C3P0 Connection Testing Not Working

StackOverflow https://stackoverflow.com/questions/20224048

Question

I am building a webapp that uses JPA, Hibernate, and C3P0 to access a MySQL database. So far, it works fine, as long as I don't go over MySQL's wait_timeout. If I try loading a page after that timeout is triggered, I get the following error, and I have to restart my application.

javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: could not prepare statement
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387) ~[hibernate-entitymanager-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310) ~[hibernate-entitymanager-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:277) ~[hibernate-entitymanager-4.2.7.Final.jar:4.2.7.Final]
at [myApplication].services.ClassroomService.findSessions(ClassroomService.java:155) ~[[myApplication].shared-1.1.6-SNAPSHOT.jar:1.1.6-SNAPSHOT]
at [myApplication].portal.resources.AdminResource.getSessions(AdminResource.java:51) ~[classes/:na]
at sun.reflect.GeneratedMethodAccessor30.invoke(Unknown Source) ~[na:na]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_40]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_40]
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381) [jersey-server-1.17.1.jar:1.17.1]
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416) [jersey-servlet-1.17.1.jar:1.17.1]
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538) [jersey-servlet-1.17.1.jar:1.17.1]
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716) [jersey-servlet-1.17.1.jar:1.17.1]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848) [javax.servlet-3.0.0.v201112011016.jar:na]
at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:263) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:178) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:62) [guice-servlet-3.0.jar:na]
at [myApplication].web.CorsFilter.doFilter(CorsFilter.java:59) [[myApplication].shared-1.1.6-SNAPSHOT.jar:1.1.6-SNAPSHOT]
at com.google.inject.servlet.FilterDefinition.doFilter(FilterDefinition.java:163) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:58) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:118) [guice-servlet-3.0.jar:na]
at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:113) [guice-servlet-3.0.jar:na]
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1419) [jetty-servlet-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455) [jetty-servlet-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557) [jetty-security-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384) [jetty-servlet-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.Server.handle(Server.java:370) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:949) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1011) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644) [jetty-http-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235) [jetty-http-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82) [jetty-server-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668) [jetty-io-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52) [jetty-io-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608) [jetty-util-8.1.11.v20130520.jar:8.1.11.v20130520]
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543) [jetty-util-8.1.11.v20130520.jar:8.1.11.v20130520]
at java.lang.Thread.run(Thread.java:724) [na:1.7.0_40]
Caused by: org.hibernate.exception.JDBCConnectionException: could not prepare statement
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:67) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:188) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:159) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1859) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1836) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1816) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.doQuery(Loader.java:900) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2526) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2512) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2342) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.Loader.list(Loader.java:2337) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:495) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:357) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:195) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1275) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:268) ~[hibernate-entitymanager-4.2.7.Final.jar:4.2.7.Final]
... 55 common frames omitted
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error:


** BEGIN NESTED EXCEPTION ** 

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
MESSAGE: Communications link failure

Last packet sent to the server was 0 ms ago.

STACKTRACE:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2985)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2871)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3414)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1885)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:116)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:56)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2040)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1837)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1816)
at org.hibernate.loader.Loader.doQuery(Loader.java:900)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342)
at org.hibernate.loader.Loader.doList(Loader.java:2526)
at org.hibernate.loader.Loader.doList(Loader.java:2512)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2342)
at org.hibernate.loader.Loader.list(Loader.java:2337)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:495)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:357)
at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:195)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1275)
at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:268)
at [myApplication].services.ClassroomService.findSessions(ClassroomService.java:155)
at [myApplication].portal.resources.AdminResource.getSessions(AdminResource.java:51)
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:606)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:263)
at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:178)
at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:62)
at [myApplication].web.CorsFilter.doFilter(CorsFilter.java:59)
at com.google.inject.servlet.FilterDefinition.doFilter(FilterDefinition.java:163)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:58)
at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:118)
at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:113)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1419)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:949)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1011)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2431)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2882)
... 80 more


** END NESTED EXCEPTION **


at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.7.0_40]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) ~[na:1.7.0_40]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.7.0_40]
at java.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[na:1.7.0_40]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.Util.getInstance(Util.java:381) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.checkClosed(ConnectionImpl.java:1098) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4076) ~[mysql-connector-java-5.1.6.jar:na]
at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4042) ~[mysql-connector-java-5.1.6.jar:na]
at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:162) ~[c3p0-0.9.2.1.jar:0.9.2.1]
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:161) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:182) ~[hibernate-core-4.2.7.Final.jar:4.2.7.Final]
... 71 common frames omitted
Nov 26, 2013 11:40:43 AM com.sun.jersey.spi.container.ContainerResponse logException
SEVERE: Mapped exception to response: 500 (Internal Server Error)
[myApplication].api.ResourceException
at [myApplication].portal.resources.AdminResource.getSessions(AdminResource.java:68)
at sun.reflect.GeneratedMethodAccessor30.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:263)
at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:178)
at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:62)
at [myApplication].web.CorsFilter.doFilter(CorsFilter.java:59)
at com.google.inject.servlet.FilterDefinition.doFilter(FilterDefinition.java:163)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:58)
at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:118)
at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:113)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1419)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:949)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1011)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:724)

I also sometimes get a JDBCConnectionException: could not extract ResultSet, but that stems from the same Communications Link Failure.

Usually, C3P0 can be configured to test whether a connection is valid before using, and I tried implementing it, but it doesn't seem to work. I'm also using Guice, and I'm thinking something is going screwy when I use @Inject to get an EntityManager.

Does anyone know what's going on here? I've looked through pretty much anything that might help, but I haven't found anything yet. I'm about to try switching to Apache DBCP to see if that works any better.

Thanks,
Tyler

PS: Here's my persistence.xml and c3p0-config.xml, in case that'll help.

persistence.xml

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
    version="2.0">
    <persistence-unit name="wam" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>myApplication.beans.AnswerBean</class>
        <class>myApplication.beans.ConfigBean</class>
        <class>myApplication.beans.CourseBean</class>
        <class>myApplication.beans.DealerBean</class>
        <class>myApplication.beans.LocationBean</class>
        <class>myApplication.beans.TrainerBean</class>
        <class>myApplication.beans.PositionBean</class>
        <class>myApplication.beans.QuestionBean</class>
        <class>myApplication.beans.SessionBean</class>
        <class>myApplication.beans.StudentBean</class>
        <!-- See '/etc/setup.txt' for how to setup using MS-SQL * Change driver/dialect
            (H2=H2Dialect / MSSQL=SQLServerDialect) * Change url below (jdbc.url)
            * Change
            user/password (jdbc.user and password) OPTIONAL: * Create Database first
            (ie maildb) * Change hbm2ddl -->
        <exclude-unlisted-classes>true</exclude-unlisted-classes>
        <shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
        <properties>
            <property name="javax.persistence.jdbc.driver" value="${portal.db.driver}" />
            <property name="javax.persistence.jdbc.url" value="${portal.db.url}" />
            <property name="javax.persistence.jdbc.user" value="${portal.db.user}" />
            <property name="javax.persistence.jdbc.password" value="${portal.db.pass}" />
            <property name="hibernate.dialect" value="${portal.db.dialect}" />
            <property name="hibernate.show_sql" value="false" />
            <property name="hibernate.connection.shutdown" value="true" />
            <property name="hibernate.generate_statistics" value="${stats}"/>
            <property name="hibernate.hbm2ddl.auto" value="${portal.db.schema}" />
            <!-- Caching -->
            <property name="hibernate.cache.region.factory_class" value="org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory"/>
            <property name="net.sf.ehcache.configurationResourceName" value="ehcache.xml" />
            <property name="hibernate.cache.use_query_cache" value="true" />
            <property name="hibernate.cache.use_second_level_cache" value="true" />
            <!-- Pooling -->
            <property name="hibernate.connection.provider_class" value="org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider" />
        </properties>
    </persistence-unit>
</persistence>

c3p0-config.xml

<c3p0-config>
    <default-config>
        <property name="acquireIncrement">3</property>
        <property name="idleConnectionTestPeriod">9</property>
        <property name="maxConnectionAge">30</property>
        <property name="maxIdleTime">10</property>
        <property name="maxPoolSize">25</property>
        <property name="maxStatements">0</property>
        <property name="minPoolSize">5</property>
        <property name="preferredTestQuery">SELECT 1</property>
        <property name="testConnectionOnCheckin">true</property>
    </default-config>
</c3p0-config>
Was it helpful?

Solution 2

As it turns out, my problem wasn't with how C3P0 was working, but how Guice was making EntityManagers. I ended up adding filter("/*").through(PersistFilter.class); where I was making my persist modules, and that fixed the problem. Granted, it revealed a couple problems with eager singletons, but I'll leave that for another thread.

OTHER TIPS

1) verify that the configuration you intend is actually the configuration that is taking hold. c3p0 pools dump their configuration to log at INFO on initialization. alternatively, you can check via JMX. if Guice is programmatically overriding the defaults you set in config, you should see that in the dumped config.

2) how are you managing your hibernate Sessions? are you close()ing them promptly, or reusing long-lived Sessions. if the latter, don't. when using a Connection pool, a Session should perform a unit-of-work defined as the full set of operations a client is able to perform without waiting for further interaction. once that work is completed, the Session should be promptly close()ed. keeping long-lived open Sessions is a terrible but unfortunately common practice; it defeats both the purpose of a Connection pool and its ability to ensure, e.g. in this case, liveness.

p.s. you're setting both testConnectionOnCheckout and testConnectionOnCheckin. that's probably overkill testConnectionOnCheckout is sufficient, simple and reliable but exacts a performance tax within clients' codepath. to avoid that tax (at cost of a bit of reliablility, combine testConnectionOnCheckin with idleConnectionTestPeriod. See http://www.mchange.com/projects/c3p0/#configuring_connection_testing

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