Java Optimization Resources

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I started this page because there no other web resources on how to optimize Java. Thankfully, that has now changed.

Optimization

• Doug Bell has an excellent article on Java optimization in JavaWorld (see also benchmarks, below).
• Paul Santa Maria shows how to benchmark and optimize a Mandelbrot Set program.
• Peter Wayner's article on Core Programming in the September 1996 issue of Byte describes the various bytecodes used for Java function calls and how to speed them up (two words: use final!).
• Paul Týma has written:
  • An article on optimizing Java in the April 1996 issue of Dr Dobbs Journal.
  • An online article on Why not to use Thread.sleep()
  • Slides and example code from a talk on Writing Fast Java Code, including a case study.

Benchmarking

There are now enough Java benchmarks out there that I've alphabetised the list and commented out some that aren't being updated anymore.

• Doug Bell's Benchmark applet is part of an excellent article on how to optimize Java.
• Bill and Paul's Excellent UCSD Benchmarks, with a great explanation of the perils of benchmarking Java and pointers to more benchmarks.
• BenchBeans is a competitor for CaffeineMark (see below), in that it attempts to measure all aspects of Java performance, including graphics.
• CaffeineMark and the Java Performance Report are probably the most quoted Java benchmark and results.
• Fhourstones 2.0 plays a perfect game of Connect 4 and times itself. A good example of a non-trivial memory- and compute-intensive benchmark.
• Java BYTEMark from BYTE magazine--sadly no results yet.
• Java Speed trials from PC Magazine--the opposite problem, results but no source.
• Jstones by Jens Steckhan concentrates on testing the performance of AWT dialog elements, and includes comparative results for different systems.
• Java vs C++ results for dense matrix calculations, from Sky Coyote.
• Linpack by Jack Dongarra and Reed Wade (with additional optimizations from this site). OSF Java test suite includes both validation and benchmarking tests. Comprehensive but also tending towards incomprehensible. -->
• Sieve of Eratosthenes and the Plasma benchmark from Wayne Rasband.

The FemtoJava project at UMD has links to other benchmarks.

Books

A few of the currently available Java books have sections on optimization:

• Teach Yourself Internet Game Programming with Java in 21 Days by Michael Morrison includes tables from this site (with my approval), and expands on some of the techniques I describe for speed and helping the compiler.
• KickAss Java Programming by Tonny Espeset gives no credit, but uses a couple of my examples (of course, it might be pure coincidence that he also chose arrayCopy, abs, and inline code using the variable x but the odds are against it...).
• Advanced Java: Idioms, Styles, Programming Tips and Pitfalls has good general advice and some specific performance analyses for hash tables, strings and vectors.
• Cutting-Edge Java Game Programming by Neil Bartlett, Steve Simkin and Chris Stranc includes techniques from and references to this site.

Java resources

• There are several excellent collections of Java links--here are just a few:
  • JavaLinks from TeamJava.
  • Java Notes from Jim George.
  • Java Programming Resources from Marty Hall.
  • Java Resources from the Infospheres project at Caltech.
• "How Do I..." from the Java Developer.