Google App Engine JSP can't deploy: java.lang.RuntimeException: Cannot get the System Java Compiler. Please use a JDK, not a JRE

Question

this is hopefully something simple but... Eclipse has been working relatively fine for everything except deploying to GAE.

I can run my GAE app locally, but when I

Answer 1

Setting -vm in eclipse.ini did not help. All other settings were seemingly pointing to the JDK. Out of desperation, I uninstalled all JREs from my system, leaving only the JDK. The consequence was that Eclipse would not start as the JDK bin directory was not on my PATH (Windows 8 here). Adding this in environment system variables got Eclipse to start. Thereafter I could deploy to app engine.