Top 5 IntelliJ IDEA Performance Tips

We use JetBrains IntelliJ IDEA Java IDE and love its features, functionality, and price point. Dealing with its performance is another matter, however. When developing Seam 2.x applications, IDEA can just crawl – and this is when sticking to just one project or SVN branch at a time. Some of the biggest performance hits our team has noticed are:

1. File indexing on IDEA startup
2. Long code completion times when editing XHTML/JSF files
3. Pauses when switching from one Java or XHTML file to another
4. Calls to Ant targets can drag on forever for no apparent reason while others time they are tidy and fast

Here is a collection of ideas on how to improve the performance of IDEA; note that not all of these will be applicable to your environment or application.  For example, we wouldn’t consider turning off local history options as this is invaluable.

1. If you’re not using Subversion or other version control system, turn off synchronized files. This can be disabled from the Settings -> General, and disabling “Synchronize Files on Frame Activation”.
2. Revert to IDEA’s original visual interface. Browse to Settings -> Appearance and select the “IDEA 4.5 Default” theme.
3. Decrease the size of local history of code changes. Even if you find this feature invaluable, you can still improve performance of IDEA by reducing the number of days of local history IDEA will store.  By default this option is set to three days!
4. Disable unused plugins. You mean you’re not developing GWT apps and you’re not working with JetGroovy?  Great, then why not disable some of those plugins?
5. Increase the IDEA Java VM heap size. I can attest to this offering much improved performance; if you can spare the memory, follow these directions:
   1. locate your Program Files/JetBrains/IDEA x.x/bin directory
   2. open idea.exe.vmoptions
   3. modify Xms, Xmx, and XX:MaxPermSize settings as needed