Problema al debuggear "Source not found"

[Ejeda88]

Se me olvidaba, el error que me salta es el siguiente:

05-nov-2014 10:42:13 org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: Servlet.service() for servlet [jsp] in context with path [/ILEAGUE] threw exception [javax.servlet.ServletException: java.lang.IncompatibleClassChangeError: Found class com.mysql.jdbc.Connection, but interface was expected] with root cause
java.lang.IncompatibleClassChangeError: Found class com.mysql.jdbc.Connection, but interface was expected
at conexion.MyDataAcces.getQuery(MyDataAcces.java:39)
at usuario.Usuario.validaUsuario(Usuario.java:73)
at org.apache.jsp.validar_jsp._jspService(validar_jsp .java:75)
at org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:722)
at org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:419)
at org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:391)
at org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:722)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBas e.invoke(AuthenticatorBase.java:462)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(A ccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.servic e(CoyoteAdapter.java:395)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:250)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.process(Http11Protocol.java:188)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProce ssor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.run Task(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)