Java Under Linux Overview

LinuxSA - May 1997 Meeting
Matthew Tippett
(mtippett@tne.net.au)

Introduction

• Java, the hottest new concept

What is Java

• Portable
• Programming Language
  • Mixture of C and Ada
  • Well defined API
• Design based on networking and Security
• Portable executable format (bytecodes)
• Created by Sun Microsystems
• Spawned browser languages such as Javascript

Java Under Linux

• Java Virtual Machine (JVM) ported to Linux
  • JDK 1.0.2 and JDK 1.1.1
  • JRE 1.1.1
  • kaffe 0.9.0
• To run java applets, either
  • Compile Java Support in Kernel
    • Run the applets/applications natively
  • Run Java Applets/Applications through the JVM

How does Java Run Natively

• Kernel detects the executable type
• Kernel starts the JVM (java or appletviewer)
  • JVMs defined in binfmt_java.c
• Runs the Java bytecodes in the JVM

What having native support does

• Full Java Development Environment

Running HTML files (Applets)

• Get html and applet classes
• Give HTML file a magic number
  • <!--APPLET-->
• Set execute bit on binary.
• Run the HTML file
• Each applet wil run in it's own window

An Example of Applets

• Animated "duke"
• PACMAN

Running Java Applications

• Compile or get a class with main() method
• Set execute bit on binary
• Run the Application

An Example of an Java Application

• Corel Office for Java

What Java May do For Linux

• Access to Commercial Applications
  • Corel Office for Java
• Allow Linux on to the Desktop as a NC

Future of Java

• Commercial Acceptance as alternative
• JIT compilers

More information

• JavaSoft's Homepage
  • Java Soft Homepage
• Applet Repositories
  • Gamelan
• Java To Linux Port
  • Blackdown Org
• Current Java Linux Port
  • JDK or JRE

Questions?

Last updated: Wednesday, 18-Jun-1997 18:11:30 CST