title: Maven compilation and run time error java.lang.AbstractMethodError: oracle.jdbc.driver.T4CConnection.isValid(I)Z on Tomcat 8 Server
body: <p>I've been converting a large Java Web App to a maven project, but I've run into an error in a handful of classes originating from the tomcat-dbcp jar.  I get the following error messages from any class that needs to use BasicDataSource objects:</p>
  
  <pre><code>javax.servlet.ServletException: java.lang.AbstractMethodError: oracle.jdbc.driver.T4CConnection.isValid(I)Z
  java.lang.AbstractMethodError: oracle.jdbc.driver.T4CConnection.isValid(I)Z
  </code></pre>
  
  <p>Now I know this jar is present on the server (as it is default in our Tomcat8 installation).  So in maven I declared this dependency as such:</p>
  
  <pre><code>&lt;dependency&gt;
      &lt;groupId&gt;org.apache.tomcat&lt;/groupId&gt;
      &lt;artifactId&gt;tomcat-dbcp&lt;/artifactId&gt;
      &lt;version&gt;8.0.26&lt;/version&gt;
      &lt;scope&gt;provided&lt;/scope&gt;
  &lt;/dependency&gt;
  </code></pre>
  
  <p>But I'm still seeing this error.  What can I do to eliminate this error?</p>