title: JDBC via JT400 works on local Apache Tomcat 8 install but fails on Apache Tomcat 8 running on server
body: <p>I have a Java application running and tested on my development workstation running Apache Tomcat 8.  I have an established IBM i (AS/400) database connection working locally using the JT400.jar file. When I build and deploy the application to our production server running Apache Tomcat 8 with the same JT400.jar file, the database connection seems to fail and I cannot figure out why.  </p>
  
  <p>I get the following "HTTP Status 500 - Servlet execution threw an exception" error:</p>
  
  <pre><code>&lt;code&gt;
  java.lang.AbstractMethodError
  org.apache.tomcat.dbcp.dbcp2.DelegatingConnection.isValid(DelegatingConnection.java:913)
  org.apache.tomcat.dbcp.dbcp2.PoolableConnection.validate(PoolableConnection.java:218)
  org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory.validateConnection(PoolableConnectionFactory.java:302)
  org.apache.tomcat.dbcp.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2164)
  org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2147)
  org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1902)
  org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1412)
  utilities.SerialSearch.doSearch(SerialSearch.java:81)
  processes.ProcessScan.getSerialScreenDetail(ProcessScan.java:66)
  processes.ProcessScan.ProcessScanRequest(ProcessScan.java:103)
  controller.MetricServlet.performTask(MetricServlet.java:145)
  controller.MetricServlet.doPost(MetricServlet.java:43)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:644)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
  org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  &lt;/code&gt;
  </code></pre>
  
  <p>What is different and how do I resolve the issue?</p>
  
  <p>Thanks!</p>