title: BIRT JDBCException "Cannot load JDBC Driver class: com.mysql.jdbc.Driver" while upgrading from 2.6 to 3.7
body: <p>I'm trying to upgrade the version of my birt-viewer on my Tomcat server, but it seems that I have an error with the loading of the JDBC driver :</p>
  
  <pre><code>    exception.error ( 1 time(s) )
  detail : org.eclipse.birt.report.engine.api.EngineException: An exception occurred during processing. Please see the following message for details:
  Cannot open the connection for the driver: org.eclipse.birt.report.data.oda.jdbc.
      org.eclipse.birt.report.data.oda.jdbc.JDBCException: Cannot load JDBC Driver class: com.mysql.jdbc.Driver. (Element ID:1351)
      at org.eclipse.birt.report.engine.executor.ExecutionContext.addException(ExecutionContext.java:1237)
      at org.eclipse.birt.report.engine.executor.ExecutionContext.addException(ExecutionContext.java:1216)
      at org.eclipse.birt.report.engine.executor.QueryItemExecutor.executeQuery(QueryItemExecutor.java:96)
      at org.eclipse.birt.report.engine.executor.TableItemExecutor.execute(TableItemExecutor.java:62)
      at org.eclipse.birt.report.engine.internal.executor.dup.SuppressDuplicateItemExecutor.execute(SuppressDuplicateItemExecutor.java:43)
      at org.eclipse.birt.report.engine.internal.executor.wrap.WrappedReportItemExecutor.execute(WrappedReportItemExecutor.java:46)
      at org.eclipse.birt.report.engine.internal.executor.l18n.LocalizedReportItemExecutor.execute(LocalizedReportItemExecutor.java:34)
      at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:65)
      at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:26)
      at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:140)
      at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.resumeLayout(HTMLInlineStackingLM.java:111)
      at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.layoutNodes(HTMLInlineStackingLM.java:160)
      at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:26)
      at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:140)
      at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:70)
      at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:26)
      at org.eclipse.birt.report.engine.layout.html.HTMLTableLM.layoutChildren(HTMLTableLM.java:132)
      at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:140)
      at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:70)
      at org.eclipse.birt.report.engine.layout.html.HTMLPageLM.layout(HTMLPageLM.java:92)
      at org.eclipse.birt.report.engine.layout.html.HTMLReportLayoutEngine.layout(HTMLReportLayoutEngine.java:100)
      at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.doRun(RunAndRenderTask.java:180)
      at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.run(RunAndRenderTask.java:77)
      at org.eclipse.birt.report.service.ReportEngineService.runAndRenderReport(ReportEngineService.java:929)
      at org.eclipse.birt.report.service.BirtViewerReportService.runAndRenderReport(BirtViewerReportService.java:973)
      at org.eclipse.birt.report.service.actionhandler.BirtRunAndRenderActionHandler.__execute(BirtRunAndRenderActionHandler.java:76)
      at org.eclipse.birt.report.service.actionhandler.AbstractBaseActionHandler.execute(AbstractBaseActionHandler.java:90)
      at org.eclipse.birt.report.presentation.aggregation.layout.EngineFragment.doService(EngineFragment.java:318)
      at org.eclipse.birt.report.presentation.aggregation.AbstractBaseFragment.service(AbstractBaseFragment.java:76)
      at org.eclipse.birt.report.servlet.BirtEngineServlet.__doGet(BirtEngineServlet.java:120)
      at org.eclipse.birt.report.servlet.BaseReportEngineServlet.doGet(BaseReportEngineServlet.java:185)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
      at org.apache.axis.transport.http.AxisServletBase.service(AxisServletBase.java:327)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
      at org.eclipse.birt.report.servlet.BaseReportEngineServlet.service(BaseReportEngineServlet.java:116)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.eclipse.birt.report.filter.ViewerFilter.doFilter(ViewerFilter.java:68)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
      at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
      at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
      at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
      at java.lang.Thread.run(Thread.java:662)
  Caused by: org.eclipse.birt.report.data.adapter.api.AdapterException: An exception occurred during processing. Please see the following message for details:
  Cannot open the connection for the driver: org.eclipse.birt.report.data.oda.jdbc.
      org.eclipse.birt.report.data.oda.jdbc.JDBCException: Cannot load JDBC Driver class: com.mysql.jdbc.Driver.
      at org.eclipse.birt.report.data.adapter.impl.DataRequestSessionImpl.execute(DataRequestSessionImpl.java:644)
      at org.eclipse.birt.report.engine.data.dte.DteDataEngine.doExecuteQuery(DteDataEngine.java:158)
      at org.eclipse.birt.report.engine.data.dte.AbstractDataEngine.execute(AbstractDataEngine.java:267)
      at org.eclipse.birt.report.engine.executor.ExecutionContext.executeQuery(ExecutionContext.java:1939)
      at org.eclipse.birt.report.engine.executor.QueryItemExecutor.executeQuery(QueryItemExecutor.java:80)
      ... 47 more
  Caused by: org.eclipse.birt.data.engine.odaconsumer.OdaDataException: Cannot open the connection for the driver: org.eclipse.birt.report.data.oda.jdbc.
      org.eclipse.birt.report.data.oda.jdbc.JDBCException: Cannot load JDBC Driver class: com.mysql.jdbc.Driver.
      at org.eclipse.birt.data.engine.odaconsumer.ExceptionHandler.newException(ExceptionHandler.java:54)
      at org.eclipse.birt.data.engine.odaconsumer.ConnectionManager.openConnection(ConnectionManager.java:177)
      at org.eclipse.birt.data.engine.executor.DataSource.newConnection(DataSource.java:224)
      at org.eclipse.birt.data.engine.executor.DataSource.open(DataSource.java:212)
      at org.eclipse.birt.data.engine.impl.DataSourceRuntime.openOdiDataSource(DataSourceRuntime.java:217)
      at org.eclipse.birt.data.engine.impl.QueryExecutor.openDataSource(QueryExecutor.java:407)
      at org.eclipse.birt.data.engine.impl.QueryExecutor.prepareExecution(QueryExecutor.java:317)
      at org.eclipse.birt.data.engine.impl.PreparedQuery.doPrepare(PreparedQuery.java:455)
      at org.eclipse.birt.data.engine.impl.PreparedDataSourceQuery.produceQueryResults(PreparedDataSourceQuery.java:190)
      at org.eclipse.birt.data.engine.impl.PreparedDataSourceQuery.execute(PreparedDataSourceQuery.java:178)
      at org.eclipse.birt.data.engine.impl.PreparedOdaDSQuery.execute(PreparedOdaDSQuery.java:145)
      at org.eclipse.birt.report.data.adapter.impl.DataRequestSessionImpl.execute(DataRequestSessionImpl.java:624)
      ... 51 more
  Caused by: org.eclipse.birt.report.data.oda.jdbc.JDBCException: Cannot load JDBC Driver class: com.mysql.jdbc.Driver.
      at org.eclipse.birt.report.data.oda.jdbc.JDBCDriverManager.findDriver(JDBCDriverManager.java:836)
      at org.eclipse.birt.report.data.oda.jdbc.JDBCDriverManager.loadAndRegisterDriver(JDBCDriverManager.java:941)
      at org.eclipse.birt.report.data.oda.jdbc.JDBCDriverManager.loadAndRegisterDriver(JDBCDriverManager.java:918)
      at org.eclipse.birt.report.data.oda.jdbc.JDBCDriverManager.doConnect(JDBCDriverManager.java:266)
      at org.eclipse.birt.report.data.oda.jdbc.JDBCDriverManager.getConnection(JDBCDriverManager.java:232)
      at org.eclipse.birt.report.data.oda.jdbc.Connection.connectByUrl(Connection.java:243)
      at org.eclipse.birt.report.data.oda.jdbc.Connection.open(Connection.java:162)
      at org.eclipse.datatools.connectivity.oda.consumer.helper.OdaConnection.open(OdaConnection.java:250)
      at org.eclipse.birt.data.engine.odaconsumer.ConnectionManager.openConnection(ConnectionManager.java:165)
      ... 61 more
  </code></pre>
  
  <p>My case is a bit special, as I don't know if I did it correcly. I explain myself.</p>
  
  <p>I have some reports that are designed with BIRT 2.6 and some others that are designed with BIRT 3.7. What I've done on my Tomcat server is that I created two repositories:
  - birt-viewer
  - birt-viewer3.7</p>
  
  <p>I put MySQL driver (<em>mysql-connector-java-5.0.8-bin.jar</em>) file in <em>birt-viewer3.7/WEB-INF/lib/</em>.</p>
  
  <p>But I still have the error. I also tried to put it in <em>birt-viewer3.7/WEB-INF/platform/plugins/</em> but the errors remains the same.</p>
  
  <p>First of all: is it possible to make two versions of the birt-viewer coexist?</p>
  
  <p>If it's possible, how can I do to solve this driver problem?</p>
  
  <p>Thanks.</p>