when trying to compile wicket-7 from HEAD it fails under OS X / JDK 1.8.0_11. Casting a NULL to generic type (T) solves the issues. This seems like some odd case of failing type inference.
The problematic source line is:
The compiler error is:
This will fix the issue:
I found that there is a fix
WICKET-5427 which does not work in most current JDK 1.8.0_11 anymore. - Could not change the wicket-6 branch since the change will break the clirr plugin (see - WICKET-5427).