Challenges and Solutions for Embedded Java Michael Wortley Computer Integrated Surgery March 1, 2001

TINI CORBA ORB Project Goal: to port Java based CORBA ORB to TINI board Problem: Converting from JDK1.3 to TINI’s embedded Java

Goals of this Presentation Provide background of Java’s benefits Show how embedded environment presents challenges to the Java platform Highlight available solutions

Main Sources “Challenges to Embedded Java” –Charlie McDowell, UC Santa Cruz –1998 PowerPoint presentation “Technical Overview of Embedded Java” –4/2000, From Sun Website

Other Sources “Java Schism?” –Rick Cook, Java Report 6/99 “About Java Technology” –Sun Website TINI software information from

Goals of this Presentation Provide background of Java’s benefits Show how embedded environment presents challenges to the Java platform Highlight available solutions

“Write Once, Run Anywhere.”

Why do Programmers like Java? Compiled and Interpreted Easy Upgrades through API JVM = Portability

Goals of this Presentation Provide background of Java’s benefits Show how embedded environment presents challenges to the Java platform Highlight available solutions

“Challenges to Embedded Java” PowerPoint Presentation by Charlie McDowell, 1998.

Key Points Java is superior to C++ in ease of development, maintenance, and portability Java API and JVM put too much stress on embedded processors Java tends to have slower execution time

Key Points Automatic garbage collection causes problems Java lacks real-time support

Java Memory Requirements Storage of Java API –up to 9 MB for JDK1.1 JVM –between 300 and 800 KB Garbage Collection Overhead –copy collectors -> requires 2x max. heap usage –conservative collectors -> memory leaks

Java Execution Time Interpreted code runs more slowly than compiled code Resolving references prior to execution reduces run time Using final and static methods can reduce dynamic dispatch of functions Garbage Collection eats memory

Garbage Collection Part of what makes Java simple Problematic for real-time applications

Java and Real-Time Applications Java lacks: –reliable methods of estimating worst case –ability to measure CPU time, memory use –enforcement of time and space budgets –real-time garbage collection IMPROVEMENTS NEEDED!

Suggested Optimizations for Embedded Java Reduce API to free memory Use final and static functions to decrease execution time Eliminate automatic garbage collection Find ways to improve real-time performance

Non-Sun Embedded Java PERC by NewMonics –real-time garbage collection VxWorks –only 628 KB JN from UCSC –JIT from Kaffe –reduced API

Goals of this Presentation Provide background of Java’s benefits Show how embedded environment presents challenges to the Java platform Highlight available solutions

“Technical Overview of Embedded Java Technology” Sun Microsystems

Improvements in Sun’s Embedded Java Configurable API Configurable JVM JavaFilter tool JavaCodeCompact JavaDataCompact

New Programming Tools JavaFilter –input source code Java API –output list of necessary API classes and methods

New Programming Tools JavaCodeCompact –input Source Code Java API list of necessary API classes and methods –output data structures in C code

New Programming Tools JavaDataCompact –input associated data files Java API –output data structures in C code

How this Relates to TINI TINI’s embedded Java is Sun compatible. Limitted API Development Tools –TINI API –TINIConvertor

Conclusions about Embedded Java Increasing complexity of embedded devices will force makers to use high level language Java’s fast development time and portability are ideal for large manufacturers Competition needed to drive advancements

So long, and thanks for all the fish.