As far as I can tell, RTP doesn't provide any tools to generate a JAR file. This is probably because RTP is completely obsolete and lacks (basically any) features.
A JAR file is just a zip archive with some special meaning to the files it contains. You can create them from the command line (see
http://docs.oracle.com/javase/tutorial/deployment/jar/build.html). If you do that, then you will need to include the class files from your RTP install: (rtp install directory)/Support/Ready Classes/hsa/ to have support for hsa.Console, etc.