Tomcat6 ignores web-inf/lib

Question

Brief: Tomcat6 can't recognize my ojdbc14.jar in WebRoot/WEB-INF/lib. I suppose I don't need to configure anything, just putting the .jar file in there and it should work.

Details:

I've created a web application and put ojdbc14.jar in WEB-INF/lib folder. When I start Tomcat6 and access an index.jsp page which creates an object that initiates a connection to my oracle database, an error occurs saying "Cannot load JDBC driver class 'oracle.jdbc.OracleDriver'". Apparently Tomcat6 can't recognize the 'oracle.jdbc.OracleDriver' class in web-inf/lib/ojdbc14.jar.

I've done some research and speculate the following reasons:

1. Tomcat6 has got some different ways of loading classes. They change it in every version released. Or
2. There is a bug with Tomcat6. I found a similar bug in Tomcat3 (see here https://bugs.eclipse.org/bugs/show_bug.cgi?id=249044). But I doubt this bug could last for so many versions.
3. Tomcat6 has included ojdbc14.jar's content in its own lib file already, and there's a conflict by adding it to web-inf/lib once more. I don't believe this, because after deleting ojdbc14.jar from WEB-INF/lib, the problem persists.

Here's my web application structure:

• WebRoot
  • WEB-INF
    • classes
      • 'A class for initiating a connection'
    • lib
      • ojdbc14.jar
  • index.jsp

---

The error:

org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot load JDBC driver class 'oracle.jdbc.OracleDriver'
    at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:766)
    at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
    at com.demo6.DataSourceExample.getConnection(DataSourceExample.java:18)
    at org.apache.jsp.index_jsp._jspService(index_jsp.java:63)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:384)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:228)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:216)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:634)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:445)
    at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: oracle.jdbc.OracleDriver
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:169)
    at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:760)
    ... 21 more

Answer 1

The stacktrace tells that you've created a DataSource as <Resource> in Tomcat's side. In that case, the JDBC driver JAR file really needs to be put in Tomcat's side as well as it's Tomcat who manages the DataSource, not your webapp. Drop it in Tomcat/lib and this exception should disappear. You could also drop it in an external folder and add its path to Tomcat's common classpath as definied by common.loader property in /conf/catalina.properties file.

Please note that you don't need to load the driver manually. Just grab the DataSource and then get the Connection from it.