Can not access a member of class X with modifiers "public" even if method is public

When upgrading from 1.4 to 1.5 none of my template is working anymore.

For example :

[javadoc] ERROR [console:logVelocityMessage] - ASTMethod.execute() : exception invoking method 'tags' in class com.sun.tools.javadoc.MethodDocImpl
[javadoc] ERROR [console:logVelocityMessage] - java.lang.IllegalAccessException: Class org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl can not access a member of class com.sun.tools.javadoc.DocImpl with modifiers "public"

The method 'tags()' is public in com.sun.javadoc.Doc, but the implementation is package protected. So the java.lang.reflect.Method object is well returned by the org.apache.velocity.util.introspection.Introspector but not accessible from templates.
The same errors occured for example for javax.servlet.http.HttpSession Weblogic's implementation which is not public, but methods are !

It's not possible to wrap all objects javax.servlet.http.HttpSession into public implementations ...

The Introspector could call method.setAccessible(true) before returning Method object : if this method has been found, it is a public method !