.: JoGa :.
 -- v0.1(alpha) --



.: Contents :. 



.: Overview :. top

JoGa is a tool for optimizing the size of a Java application or api. Therefore JoGa analyses the whole program and determines unused classes, methods, and fields that can be removed from the program. JoGa also performs some optimization techniques to further reduce program size. A size reduction of up to 80% was observed.

Currently following optimization techniques are implemented:

  • removing unused classes, methods and fields
  • removing superfluous byte code from methods
  • merge classes together
  • inline methods
  • rename packages, classes, methods and fields
  • create a zip/jar file


Because JoGa is an extension of the Jopt tool it also includes the following optimizations:

  • optimize byte code
  • remove debug infos
  • compress constant pool

(for more information about Jopt see: http://www-i2.informatik.rwth-aachen.de/~markusj/jopt)

JoGa is written in 100% pure Java and comes with an easy to use graphical user interface. After having read this short documentation, you should be able to optimize your Java application or api.


.: Requirements :.top

JoGa will run on any Java Virtual Machine that supports Sun's Java 2 specification or better. Although JoGa was written, compiled, and tested under jdk1.3 and Linux other OSes for which a suitable JVM is available should also work. A Java 2 Runtime Environment is available from http://java.sun.com. For Linux I recommend you use the JRE from IBM which you can find at http://www.ibm.com.


.: Installation :. top

To install JoGa first extract the downloaded file joga.zip to any directory of your choice. This will create two new files. One is this README file and the other one is a Java jar file named JoGa.jar which contains the program. Do not extract the JoGa.jar file! To run JoGa from a command line change directory to where JoGa.jar file is located. Then type $:java -jar JoGa.jar.
Alternatively you can add JoGa.jar with it's complete path to your CLASSPATH environment variable. Then you can directly execute JoGa by typing $:java JoGa at the command line.
Most platforms can launch a jar file by using a platform specific mechanism that launches executables JARs. For example, on Windows you can run JoGa by double-click the JoGa.jar icon.


.: Using JoGa :. top

This gives only a quick introduction of how to use JoGa.
To optimize an Java application or API simply press the add-Button and either choose a jar-file, a directory or the soley class files one after another. From the optimization menu you can select the optimizations you want JoGa to perform on the program. By default all implemented optimizations are selected. You can then press the start-Button. The optimization starts by analysing all class files. JoGa will ask you to verify some needed information during the analyse step. First of all if your classes use Java's reflection API or some native methods JoGa will detect it and ask you to protect all referenced classes. After that you have to verify the recognized type of program, that means if your classes build an applet, application or an API. Depending on this selection you also have to verify the determined main class, i.e. the entry point of the program. This was the last interaction and the rest will run fully automatic. When finished JoGa will store the optimized class files in a new directory named JoGaDIR which you can find in the directoy of the original class files.


.: Notes :.top

JoGa is a work in progress and should be considered as an unfinished application. As bugs are fixed and features are added, JoGa will reach a label of stability. At which point I will determine whether to release it to public as version 1.0

JoGa is freeware and comes with absolutly no warranty.

Please feel free to send any bug reports, questions and/or ideas to houben@nq4.de


by Arnd Houben
Last update: 12/20/2001