2014-06-11 18:26:48,645 WARN [org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLValidConnectionChecker] (XNIO-1 task-2) Unexpected error: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [rt.jar:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_05]
at java.lang.reflect.Method.invoke(Method.java:483) [rt.jar:1.8.0_05]
at org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLValidConnectionChecker.isValidConnection(MySQLValidConnectionChecker.java:83) [ironjacamar-jdbc-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.isValidConnection(BaseWrapperManagedConnectionFactory.java:1301) [ironjacamar-jdbc-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnection.checkValid(BaseWrapperManagedConnection.java:502) [ironjacamar-jdbc-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.matchManagedConnections(XAManagedConnectionFactory.java:553) [ironjacamar-jdbc-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreArrayListManagedConnectionPool.getConnection(SemaphoreArrayListManagedConnectionPool.java:377) [ironjacamar-core-impl-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.core.connectionmanager.pool.AbstractPool.internalTestConnection(AbstractPool.java:740) [ironjacamar-core-impl-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.jca.core.connectionmanager.pool.strategy.OnePool.testConnection(OnePool.java:91) [ironjacamar-core-impl-1.1.5.Final.jar:1.1.5.Final]
at org.jboss.as.connector.subsystems.common.pool.PoolOperations$TestConnectionInPool.invokeCommandOn(PoolOperations.java:206) [wildfly-connector-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.connector.subsystems.common.pool.PoolOperations$1.execute(PoolOperations.java:87) [wildfly-connector-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:606) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.AbstractOperationContext.doCompleteStep(AbstractOperationContext.java:484) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.AbstractOperationContext.completeStepInternal(AbstractOperationContext.java:281) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:276) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:271) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:145) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.domain.http.server.DomainApiHandler.handleRequest(DomainApiHandler.java:170)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler$1.run(SubjectDoAsHandler.java:72)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler$1.run(SubjectDoAsHandler.java:68)
at java.security.AccessController.doPrivileged(Native Method) [rt.jar:1.8.0_05]
at javax.security.auth.Subject.doAs(Subject.java:422) [rt.jar:1.8.0_05]
at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:94) [wildfly-controller-8.1.0.Final.jar:8.1.0.Final]
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler.handleRequest(SubjectDoAsHandler.java:68)
at org.jboss.as.domain.http.server.security.SubjectDoAsHandler.handleRequest(SubjectDoAsHandler.java:63)
at io.undertow.server.handlers.BlockingHandler.handleRequest(BlockingHandler.java:50)
at org.jboss.as.domain.http.server.DomainApiCheckHandler.handleRequest(DomainApiCheckHandler.java:83)
at io.undertow.security.handlers.AuthenticationCallHandler.handleRequest(AuthenticationCallHandler.java:52)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:177)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:727)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [rt.jar:1.8.0_05]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [rt.jar:1.8.0_05]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_05]
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 474,385 milliseconds ago. The last packet sent successfully to the server was 124,248 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [rt.jar:1.8.0_05]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [rt.jar:1.8.0_05]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [rt.jar:1.8.0_05]
at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [rt.jar:1.8.0_05]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1137)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3715)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3604)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4149)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2615)
at com.mysql.jdbc.ConnectionImpl.pingInternal(ConnectionImpl.java:4378)
at com.mysql.jdbc.ConnectionImpl.ping(ConnectionImpl.java:4355)
at com.mysql.jdbc.jdbc2.optional.ConnectionWrapper.ping(ConnectionWrapper.java:867)
... 35 more
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:3161)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3615)
... 41 more
Are you sure there wasn't a DB server downtime or some such thing? You also note that the DB server is hosted on a VM, perhaps that's playing a part in slowing things down and maybe even communication failures?