Oops. My mistake. The WARNING IS FALSE but eventually becomes true. These files only SEEM to be java source files. BUT as they are in "catgen/in/javasrc" they are actually merely templates for generated java files which we DO want to contain the WARNING. We are just supposed to know to ignore the comment when we see it in the template file but to pay attention to it when we see it in the identical "generated source" file. 
Sadly, the warning can not be generated only in the generated files to which it applies because the generation tool (called "cp") is not smart enough to do this. Maybe we could use something new and fancy like "sed" to do this. Then we'd have to cross-compile or something for future ports to DOS-like environments.

All of this of course was "broken when you found it". Sorry for my confusion. This "feature" should only be a stumbling block for noobs -- like high tech hazing -- so, I have no excuse. At this rate, I'll never make wizard.