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FAQ How do I increase the permgen size available to Eclipse?

Revision as of 11:30, 14 July 2010 by Daniel (Talk | contribs) (Eclipse and Sun VMs on Windows)

If you see java.lang.OutOfMemoryError: PermGen space errors, you need to increase the permanent generation space available to Eclipse.

PermGen is the permanent generation of objects in the VM (Class names, internalized strings, objects that will never get garbage-collected). An easy, if somewhat memory-hungry fix is to enlarge the maximum space for these objects by adding

eclipse [normal arguments] -vmargs -XX:PermSize=64M -XX:MaxPermSize=128M [more VM args]

The arguments after -vmargs are directly passed to the VM. Run java -X for the list of options your VM accepts. Options starting with -X are implementation-specific and may not be applicable to all VMs.

You can also put the extra options in eclipse.ini.

Eclipse and Sun VMs on Windows

Eclipse 3.3 supports a new argument to the launcher: --launcher.XXMaxPermSize. On Windows, Eclipse 3.3 ships with the following lines in the eclipse.ini file:


With the above arguments, if the VM being used is a Sun VM and there is not already a -XX:MaxPermSize= VM argument, then the launcher will automatically add -XX:MaxPermSize=256m to the list of VM arguments being used. The 3.3 launcher is only capable of identifying Sun VMs on Windows.

Note: Eclipse 3.6 and below on Windows has a bug with Oracle/Sun JDK 1.6.0_21 (July 2010) where the launcher cannot detect a Oracle/Sun VM, and therefore does not use the correct PermGen size. If you are using either of this version, add the -XX flag to the eclipse.ini as described above.

Note: Eclipse 3.3.1 has a bug where the launcher cannot detect a Sun VM, and therefore does not use the correct PermGen size. It seems this may have been a known bug on Mac OS X for 3.3.0 as well. If you are using either of these platform combinations, add the -XX flag to the eclipse.ini as described above.

The best way to really eliminate PermGen problems is to run Eclipse against non-Sun JVM, e.g. IBM J9 and BEA WebRockit. Note that while "normal" download of Windows version of IBM JVM is intended only for upgrade of old IBM computers, IBM site contains special distribution of Eclipse prepackaged with IBM JVM. You may use this distribution directly of extract JVM from it. Note that you don't need to install the same JVM in the JRE list inside Eclipse if you do not wish to.

See Also:

This FAQ was originally published in Official Eclipse 3.0 FAQs. Copyright 2004, Pearson Education, Inc. All rights reserved. This text is made available here under the terms of the Eclipse Public License v1.0.

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