Inside Java

Personnal Java - Overview

 

What is it?

new.gif (964 bytes) January 8, 1998 -- It's Final! Sun Microsystems Inc. announced today that the PersonalJava platform 1.0 reference implementation has been released to licensees.

PersonalJava is a new Java Application Environment for network-connected devices for use in the home, office, or while mobile. PersonalJava is designed to reduce the overall cost of porting to multiple consumer device platforms.

Consumer devices need to be web-connectable, meaning they must support the download and execution of applets and application. For example, PersonalJava on a webphone provides consumers easy access to the Internet and specialized network services.

PersonalJava allows Java applications to be downloaded automatically to the end-user, for example, a Java applet that displays the user's stock portfolio or the weather conditions of a travel destination.

The API

Sun released the PersonalJava Specification 1.0 on September, 29th. This specification is a subset of the JDK 1.1 API, with a new set of APIs designed to support small devices.

This API defines which packages are required, optionals, modified or unsupported. The following packages are included in PersonalJava:

Tools

Sun also created a new suite of tools to develop Personnal Java applications. The development consists in four steps:

1.PersonalJava or EmbeddedJava code development.
2.Converting all Java code to ROM format.
3.Converting auxiliary files to ROM format.
4.Producing the final ROM image.

In the first phase, developers use these tools to configure (JavaConfig) and estimate resource requirements, compile (Javac), check if the .class files adhere to the target specification ( PersonnalJava or EmbeddedJava), build images and combine multiples .class files into a single one (JavacodeCompact).

During the second phase, JavaCodeCompact is used to produce a target-system depended input file in an assembly language. This assembly file contains only tables of data which contain the Java bytecode, and a few instructions in assembler commands.

The third phase uses JavaDataCompact. Applets or applications usually require data files, such as images. This tool places all the data file into tables of data included in the .s assembly file.

In the final phase, all files are linked together to produce a .out executable file. This is done using the standard link program provided with RTOS linker. It's also possible at this moment to include native code and RTOS code.

Resellers

This is a list of PersonalJava Resellers provided by Sun:

 

This page was last updated 06 March 1998