Propeller JVM (Javelin Virtual Machine)

  • Run Java(TM) 1.1 code on Propeller
  • Allows lower cost hardware like Spin Stamp
  • Supports Propeller Proto Board hardware
  • Supports any minimalist Propeller hardware
  • Flexibile MIT licensed open source JVM
  • Leverages the extensive Javelin class library
  • Twice performance of Javelin in some tests
  Java is a trademark of Sun Microsystems and Oracle Parallax Javelin Stamp Parallax Spin Stamp

But what is a Javelin? !

Javelin Stamp is a Parallax product introduced near the turn of the century when Java was "the hot item" to put on micro-controllers in some form. Java is still produced in chips today, but does not maintain a great following. Over the years, a few people invested much time in the Javelin and the library. Peter Verkaik was the major contributor in these areas for Javelin. In 2010, Parallax announced end of life status for the Javelin. Since the Javelin is used in many applications, and the library code base is still active, having a compatible Propeller based Javelin Java Virtual Machine has value.

The PropellerJVM is targeted as a way to get Java running on Propeller and Javelin is a familiar product with an extensive class library. As such, it is good to know more about what Javelin is. The best resource is Parallax. Links below provide more information on the Javelin Stamp:

Javelin Stamp     Javelin Starter Kit     Javelin Manual Manual Errata     Javelin Downloads

Getting started with the Propeller JVM

Hardware and Software Usage Summary
To get started you will need hardware and software.

The JVM will run on one of these hardware configurations. A fully tested and deployable JVM micro-controller application will require hardware. Java code targeted for the JVM may be developed and tested with standard Java, but there are substantial differences between that and Javelin (Java 1.1) code. The Javelin library for example uses the stamp library Terminal class for input rather than Scanner class.

Your Javelin Java application will run on the JVM. To build your application and the JVM, certain tools are required. Downloading and setting up the software for development is described in the software page.

Code written for Javelin will run on Propeller. There are some differences: Code/data size is 32KB on Javelin -vs- about 20KB on Propeller. More hardware IO pins are available for some Propeller hardware than Javelin.

Software may be installed and used on Linux and Windows.

Today the JVM and Java application are packaged in one binary and downloaded to the Propeller micro-controller. Future supported hardware products allowing for larger Java applications will require different behavior.

There is no support for the Javelin IDE and support is not planned. Javelin applications are built using the IBM jikes compiler and Javelin linker.