I’m working on a Flex project that is just kicking Eclipse in the ass. It takes forever to build and I keep getting out of memory errors. Finally, I complained about the issue on Twitter and @tomcornilliac was nice enough to twit back that I needed to give Eclipse a bigger heap by editing the eclipse.ini file.

Simple enough. My eclipse.ini file is in the root folder of the Eclipse installation and looks like this:

-showsplash
org.eclipse.platform
–launcher.XXMaxPermSize
256M
-vmargs
-Dosgi.requiredJavaVersion=1.5
-Xms40m
-Xmx256m
-Djava.net.preferIPv4Stack=true
-Djava.net.preferIPv4Stack=true

I changed the two bolded lines to:

-Xms256m
-Xmx512m

And everything runs much faster and I haven’t gotten any of those pesky errors since.

You can also go Window > Preferences > General > Show heap status to get a display of how much RAM Eclipse has to work with and how much it’s actually using. Very handy to turn that on to see if you need to increase your RAM allowance.

Here’s a link to a few other suggested performance improvements you can do to Eclipse/FlexBuilder.