Goodbye restarts, Hello Javaleon

Java class reloader Javeleon hits 2.0 release

Chris Mayer

The dynamic update system enters its second series, promising a ‘highly improved’ reloading experience

The world of super-fast class reloaders has certainly become a
competitive one in recent years. With JRebel and DCEVM both
innovating, what can the Javeleon class reloading system offer this
time round in 2.0 that breaks the mould?

Seemingly quite a lot. The University of Southern Denmark is
behind the tool that lets you see code changes in your
running application immediately, and has spent a lot of
work boosting performance of Javeleon to further enhance
productivity in your working environment. Startup time is much
quicker, whilst runtime performance overhead is substantially
lowered. Several issues are fixed too, such as a cloning objects
bug, resolved JDK 7 problems and a native method issue.

The team behind Javeleon also say that 2.0 provides better
support for Java dynamic proxies and AspectJ. The ties to the
NetBeans IDE are fairly obvious, with Javeleon fitting best into
that IDE with strong integration. Javeleon not
only comes with out-of-the-box integration
for NetBeans Platform-based applications, but
also supports GUI development on the IDE.

benchmark tests
(shown below) show that Javeleon is certainly
catching up with JRebel in terms of performance, but there’s really
not too much between the two. If you’re still uncertain of which to
pick, the comparative features list
might help you decide – JRebel has the edge on instant builds and
reloading resources, whilst Javeleon can replace superclasses.
There’s certainly worth in both. If you’re somehow not using a
class reloader in your environment, where have you been?

Ready to skip those infuriating restarts? Download Javeleon
2.0 here
, for either standalone Javeleon or the NetBeans
plugin. Javeleon is a JVM-plug-in that requires to
be configured as a JVM agent. This is
done by using the “-javaagent” argument in your
JVM launch settings. The team are currently looking for JBoss 7.1
beta testers ahead of moving across to that area,
contact if you want to help out

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