Workaround for webapp classloader regression in DevMode

Allow org.eclipse.jetty classes and friends (Jasper, Xerces) to be
loaded from the classpath without adding the containing JAR
(probably gwt-dev) to the webapp classloader.
Jasper and Xerces were previously added as system classes (from
Jetty's terminology), taking precedence over JARs from WEB-INF/lib;
this change make them "normal" classes with a special classloader
fallback behavior (fallback to the system classloader, without adding
the containing JAR to the webapp classloader).

Also fixes resource loading when trying to load server resources (from
Jetty's terminology) by not allowing them to be loaded from the

Bug: issue 8526, issue 8585
(cherry picked from commit abb1c56838dc71d7b3c30ded6a687aeffae8d848)
Change-Id: I77611c40bd16ecb39d5c288b8e82647f65f47c86
1 file changed