There's a connection pool configured in Wildfly 10 to connect to MySQL database. A Spring REST app is deployed and uses the connection pool. Problem is, it looks like it maintains the opened connections like they were alive, but when DB timeout passes and application requests a connection from pool, it fails with the next error:

code
2016-08-20 10:05:05,484 DEBUG [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-17) could not extract ResultSet [n/a]: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 3,999,184 milliseconds ago. The last packet sent successfully to the server was 47 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:988)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3552)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3452)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3893)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1962)
at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:504)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:70)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2117)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1905)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1881)
at org.hibernate.loader.Loader.doQuery(Loader.java:926)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:343)
at org.hibernate.loader.Loader.doList(Loader.java:2609)
at org.hibernate.loader.Loader.doList(Loader.java:2592)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2424)
at org.hibernate.loader.Loader.list(Loader.java:2419)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:502)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:371)
at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1450)
at org.hibernate.query.internal.AbstractProducedQuery.doList(AbstractProducedQuery.java:1402)
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1374)
at org.hibernate.query.internal.AbstractProducedQuery.getSingleResult(AbstractProducedQuery.java:1420)
at com.hayturno.spring.dao.PacienteDAO.getPatientInfo(PacienteDAO.java:28)
at com.hayturno.spring.service.AuthorizationService.isValidUser(AuthorizationService.java:29)
at com.hayturno.spring.controller.BaseController.authorizeUser(BaseController.java:41)
at com.hayturno.spring.controller.DoctorController.getDoctorsList(DoctorController.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
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:3004)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3462)
... 73 more

2016-08-20 10:05:05,488 WARN [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-17) SQL Error: 0, SQLState: 08S01
2016-08-20 10:05:05,488 ERROR [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-17) Communications link failure

The last packet successfully received from the server was 3,999,184 milliseconds ago. The last packet sent successfully to the server was 47 milliseconds ago.
2016-08-20 10:05:05,493 DEBUG [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-17) Exception clearing maxRows/queryTimeout [No operations allowed after statement closed.]
2016-08-20 10:05:05,499 DEBUG [org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl] (default task-17) JDBC transaction marked for rollback-only (exception provided for stack trace): java.lang.Exception: exception just for purpose of providing stack trace
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.markRollbackOnly(JdbcResourceLocalTransactionCoordinatorImpl.java:254)
at org.hibernate.engine.transaction.internal.TransactionImpl.setRollbackOnly(TransactionImpl.java:143)
at org.hibernate.Transaction.markRollbackOnly(Transaction.java:68)
at org.hibernate.internal.AbstractSharedSessionContract.markForRollbackOnly(AbstractSharedSessionContract.java:340)
at org.hibernate.internal.ExceptionConverterImpl.handlePersistenceException(ExceptionConverterImpl.java:271)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:148)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1383)
at org.hibernate.query.internal.AbstractProducedQuery.getSingleResult(AbstractProducedQuery.java:1420)
at com.hayturno.spring.dao.PacienteDAO.getPatientInfo(PacienteDAO.java:28)
at com.hayturno.spring.service.AuthorizationService.isValidUser(AuthorizationService.java:29)
at com.hayturno.spring.controller.BaseController.authorizeUser(BaseController.java:41)
at com.hayturno.spring.controller.DoctorController.getDoctorsList(DoctorController.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
code

Looking above this, we have the next output from JCA:

code
2016-08-20 08:59:21,290 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 08:59:31,292 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:00:13,707 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:00:13,707 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:00:13,708 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471704913708) [2/30]
2016-08-20 09:01:31,296 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:01:41,298 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:02:43,709 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:02:43,709 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:02:43,711 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705063710) [2/30]
2016-08-20 09:03:41,302 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:03:51,304 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:05:13,712 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:05:13,712 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:05:13,716 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705213715) [2/30]
2016-08-20 09:05:51,307 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:06:01,308 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:07:43,716 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:07:43,717 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:07:43,717 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705363717) [2/30]
2016-08-20 09:08:01,310 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:08:11,312 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:10:11,315 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:10:13,718 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:10:13,718 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:10:13,718 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705513718) [2/30]
2016-08-20 09:10:21,318 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:12:21,322 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:12:31,324 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:12:43,719 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:12:43,719 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:12:43,719 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705663719) [2/30]
2016-08-20 09:14:31,328 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:14:41,331 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:15:13,720 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:15:13,722 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705813721) [2/30]
2016-08-20 09:15:13,720 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:16:41,334 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:16:51,336 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:17:43,723 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:17:43,724 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471705963724) [2/30]
2016-08-20 09:17:43,724 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:18:51,340 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:19:01,342 DEBUG [org.jboss.ejb.client.txn] (Periodic Recovery) Send recover request for transaction origin node identifier 1 to EJB receiver with node name centos-2gb-nyc1-01
2016-08-20 09:20:13,725 DEBUG [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) Notifying pools, interval: 150000
2016-08-20 09:20:13,725 DEBUG [org.jboss.jca.core.connectionmanager.pool.idle.IdleRemover] (IdleRemover) Notifying pools, interval: 150000
2016-08-20 09:20:13,727 DEBUG [org.jboss.jca.core.connectionmanager.pool.strategy.OnePool] (IdleRemover) HayTurno3DS: removeIdleConnections(1471706113727) [2/30]
...
code

It looks like pool validates idle connections and kills the idle ones and it should create new ones, but it doesn´t work. Why it cannot have valid connections? Also, from where does it get 150000 interval?