[CLK-256] ClassNotFoundException in StandardClassLoader (Tomcat)

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Component/s: core
• Environment: 1.4RC1; Tomcat 5.0.16
• Assignee: Malcolm Edgar
• Reporter: harryw
• Created: 01/Nov/07 11:17
• Updated: 04/Jan/08 17:35
• Resolved: 28/Dec/07 07:42

Description

Problem with ClassNotFoundException for custom format class configured in click.xml (the same applies if a custom error page is configured for instance).
This exception occurs for
private void loadFormatClass(Element rootElm)
....
formatClass = Class.forName(classname);
.....

To reproduce setup Tomcat directories like:

• shared
• - lib
  click-1.4RC1.jar
  click-extracts
• webapps
  • • myapp/WEB-INF/classes/com.mycorp.com/CustomFormat.class
      • myapp/WEB-INF/lib (empty)

When I debugged this issue I found, that when the click servlet is inited Class.forName(classname) uses Tomcat's StandardClassLoader which searches for the class only in tomcat\shared\classes etc. but NOT in WEB-INF\classes.

One workaround to solve this issue would be to copy the click....jar's to the WEB-INF/lib directory - yes then the problem does not occur, probably because the click servlet is loaded by the WebAppClassloader (sorry I had not time to investigate it further). However in our environment we store the libs in a shared location.

The fix is to use the following code instead (this worked):
....
// get the context classloader e.g. WebappClassLoader
ClassLoader webCl = Thread.currentThread().getContextClassLoader();
formatClass = Class.forName(classname, true, webCl);
....
NOTE: There are 2 occurences of Class.loadClass in ClickApp to fix.

Please review and fix this for the next release.

Thx.