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J2ME JAR size optimization:
Decrease your JAR's size
J2ME devices have JAR File
restrictions and this could vary from 32 KB to 200KB and over. Depending on the
devices your application is ported to, JAR sizes have to be decreased, here are
some of the tricks you can use for decreasing the JAR file sizes. Never start
coding with optimization in mind. Only optimize at the fag end of the project
after all code readability is also important. Intermediate device deployments
can also be done to check the device compatibility and to get a fair idea of how
your application works on the target devices.
Thumb rule for coding J2ME
applications is modular programming approach. Never use design patterns when
the target devices consist of low end devices. We may also think about two code
bases one for high end devices with colorful images etc and another for low
end devices with bare bone functionality.
Obfuscation is a technique
used not only to protect make your source code unreadable but also comes with
added advantage of smaller JAR file memory footprint. The most popular open
source obfuscators are ProGuard and RetroGuard.
Reduce methods if possible.
Condense multiple methods to a single method.
Reduce try-catch blocks
to bare minimum.
Use lower versions of
JDK while packaging JAR files, JAR File size created using JDK 1.3 is 5% to
20% lesser than those created with JDK1.4.
Remove redundant features.
Some times you may have to sacrifice some of the essential features.
Split your application
to multiple JAR files or services.
Reduce number of classes.
See if some of the classes can be clubbed together into a single class.
Remove Array instantiations
and use Strings instead. This reduces class file size.
Ask your graphic designer
if he can reduce the image sizes.
Unlike desktop or web applications
J2ME comes with the extra baggage of file sizes. Make sure at the design stage
all these issues are taken care and a careful analysis should be done regarding
the JAR file sizes.
