8026374: javac accepts void as a method parameter
Summary: Changing Check.validate to reject void types.
Reviewed-by: jjg, vromero
^build/
^dist/
/nbproject/private/
^src/share/tools/hsdis/build/
^src/share/tools/IdealGraphVisualizer/[a-zA-Z0-9]*/build/
^src/share/tools/IdealGraphVisualizer/build/
^src/share/tools/IdealGraphVisualizer/dist/
^.hgtip
.DS_Store