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Challenges and Solutions for Embedded Java

Challenges and Solutions for Embedded Java

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Challenges and Solutions for Embedded Java

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

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

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

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

  5. Other Sources • “Java Schism?” • Rick Cook, Java Report 6/99 • “About Java Technology” • Sun Website • TINI software information from www.iButton.com

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

  7. “Write Once, Run Anywhere.”

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

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

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

  11. 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

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

  13. 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

  14. 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

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

  16. 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!

  17. 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

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

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

  20. “Technical Overview of Embedded Java Technology” Sun Microsystems http://java.sun.com/products/embeddedjava/overview.html

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

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

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

  24. New Programming Tools • JavaDataCompact • input • associated data files • Java API • output • data structures in C code

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

  26. 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

  27. So long, and thanks for all the fish.