The internal compiler allows to use Generics ("GJ Input" = true). That seems to 
work nicely, better than using the external compiler and javac.jar from JSR 14, 
because that one generates wrong line numbers for compile errors.
With Generics enabled, you sometimes get "unchecked warnings" from the compiler 
like this:
Note: com\apag\p2plus\p2objects\ObjectCollection.java uses unchecked operations.
Note: Recompile with -warnunchecked for details.

That's OK. But if you want to see details to these warnings, you have to supply 
the -warnunchecked option to the generics compiler. This option cannot be set 
for the internal compiler.