Tomcat6 - Connection has already been closed -

since few days, seeing error 'connection has been closed' in production environment:

following datasource configuration:

<resource defaultautocommit="true" defaultreadonly="false"         driverclassname="oracle.jdbc.oracledriver"         factory="org.apache.tomcat.jdbc.pool.datasourcefactory"         fairqueue="false" initialsize="10"         jdbcinterceptors="connectionstate" jmxenabled="true"         logabandoned="true" maxactive="100" maxidle="50"         maxwait="30000" minevictableidletimemillis="5000"         minidle="10" name="jdbc/oracleapps" password="apps"         removeabandoned="false" removeabandonedtimeout="60"         testonborrow="true" testonreturn="false"         suspecttimeout="60"         testwhileidle="true" timebetweenevictionrunsmillis="5000"         type="javax.sql.datasource"         url="jdbcurl"         useequals="false" username="apps" validationinterval="30000" validationquery="select 2+2 dual"/> 

i have tried configuration various ways still throws same error. idea appreciated:

java.sql.sqlexception: connection has been closed. @ org.apache.tomcat.jdbc.pool.proxyconnection.invoke(proxyconnection.java:118) @ org.apache.tomcat.jdbc.pool.jdbcinterceptor.invoke(jdbcinterceptor.java:94) @ org.apache.tomcat.jdbc.pool.interceptor.connectionstate.invoke(connectionstate.java:140) @ $proxy0.createstatement(unknown source) @ cx.pooleddataconnection.open(unknown source) @ cx.crm.opportunity.opportunityhome.getopportunity(unknown source) @ cx.crm.opportunity.opportunityhome.getopportunitybyprimarykey(unknown source) @ org.apache.jsp.jsp.wow.convertquote_jsp._jspservice(convertquote_jsp.java:559) @ org.apache.jasper.runtime.httpjspbase.service(httpjspbase.java:70) @ javax.servlet.http.httpservlet.service(httpservlet.java:717) @ org.apache.jasper.servlet.jspservletwrapper.service(jspservletwrapper.java:386) @ org.apache.jasper.servlet.jspservlet.servicejspfile(jspservlet.java:313) @ org.apache.jasper.servlet.jspservlet.service(jspservlet.java:260) @ javax.servlet.http.httpservlet.service(httpservlet.java:717) @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:290) @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:206) @ cx.filter.orginalurlfilter.dofilter(unknown source) @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:235) @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:206) @ cx.appblockerfilter.dofilter(unknown source) @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:235) @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:206) @ org.apache.catalina.core.standardwrappervalve.invoke(standardwrappervalve.java:233) @ org.apache.catalina.core.standardcontextvalve.invoke(standardcontextvalve.java:191) @ org.apache.catalina.authenticator.authenticatorbase.invoke(authenticatorbase.java:563) @ org.apache.catalina.core.standardhostvalve.invoke(standardhostvalve.java:127) @ org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:102) @ org.apache.catalina.core.standardenginevalve.invoke(standardenginevalve.java:109) @ org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:298) @ org.apache.coyote.ajp.ajpprocessor.process(ajpprocessor.java:446) @ org.apache.coyote.ajp.ajpprotocol$ajpconnectionhandler.process(ajpprotocol.java:372) @ org.apache.tomcat.util.net.jioendpoint$socketprocessor.run(jioendpoint.java:409) @ java.util.concurrent.threadpoolexecutor$worker.runtask(threadpoolexecutor.java:886) @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:908) @ java.lang.thread.run(thread.java:662) 

in case happened when there many open connections in pool , in methods called con.close() more once. in finally(s) had following code.

    {         try {               if (con != null) {                  con.close();                }         } catch (sqlexception e) {}     } 

this doesn't guarantee connection not closing.

also tomcat-jdbc.jar version old. replaced versión 7.0.55 latest available versión jdk 1.6 , works fine calling close method serveral times.