Jump is a program that allows developers to write JavaTM code for the Palm OS based handheld devices from Palm and others. This has nothing to do with the Internet, HTTP, or the World Wide Web, and in particular will not allow you to run or write Java "applets". It does allow you to use a well-designed, easy to learn language to write applications for the Palm.
Jump works by reading the .class files produced by a Java compiler, creating 68000 assembly language .asm files as output. The .asm files are then assembled by Pila (the Pilot Assembler) to produce a .prc file which can be loaded directly into the Palm. Jump is essentially the "back end" of a compiler (a Java source-to-bytecode compiler is the "front end").
The .prc files created by Jump are self-contained and do not require any Java runtime support to be present on the Pilot.Jump is open source so it's completely free.
The current version can be found at http://sourceforge.net/projects/jump. The kit contains documentation, sample applications and source code.
Watch the newsgroup pilot.programmer.jump on the server news.superwaba.net.
Pilrc (the Pilot Resource Compiler) is not strictly required but makes resource creation easier. The latest version is found at Aaron Ardiri's site www.ardiri.com. I recommend using Aaron's version, mainly because it has the -R command line switch that produces a Jump-compatible .res file (listing the file names of the binary resource files to be included).