Posted By: Craig Angus
What are the best JVM settings you have found for running Eclipse?
It is that time of year again: “eclipse.ini take 3” the settings strike back!
Eclipse Helios 3.6 and 3.6.x settings
- based on runtime options,
- and using the Sun-Oracle JVM 1.6u21 b7, released July, 27th (
some some Sun proprietary options may be involved).
(by “optimized”, I mean able to run a full-fledge Eclipse on our crappy workstation at work, some old P4 from 2002 with 2Go RAM and XPSp3. But I have also tested those same settings on Windows7)
WARNING: for non-windows platform, use the Sun proprietary option
-XX:MaxPermSize instead of the Eclipse proprietary option
That is: Unless you are using the latest jdk6u21 build 7.
See the Oracle section below.
-data ../../workspace -showlocation -showsplash org.eclipse.platform --launcher.defaultAction openFile -vm C:/Prog/Java/jdk1.6.0_21/jre/bin/server/jvm.dll -vmargs -Dosgi.requiredJavaVersion=1.6 -Declipse.p2.unsignedPolicy=allow -Xms128m -Xmx384m -Xss4m -XX:PermSize=128m -XX:MaxPermSize=384m -XX:CompileThreshold=5 -XX:MaxGCPauseMillis=10 -XX:MaxHeapFreeRatio=70 -XX:+CMSIncrementalPacing -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:+UseFastAccessorMethods -Dcom.sun.management.jmxremote -Dorg.eclipse.equinox.p2.reconciler.dropins.directory=C:/Prog/Java/eclipse_addons
p2.reconciler.dropins.directory to an external directory of your choice.
See this SO answer.
The idea is to be able to drop new plugins in a directory independently from any Eclipse installation.
The following sections detail what are in this
The dreaded Oracle JVM 1.6u21 (pre build 7) and Eclipse crashes
Andrew Niefer did alert me to this situation, and wrote a blog post, about a non-standard vm argument (
-XX:MaxPermSize) and can cause vms from other vendors to not start at all.
But the eclipse version of that option (
--launcher.XXMaxPermSize) is not working with the new JDK (6u21, unless you are using the 6u21 build 7, see below).
final solution is on the Eclipse Wiki, and for Helios on Windows with 6u21 pre build 7 only:
- downloading the fixed eclipse_1308.dll (July 16th, 2010)
- and place it into
That’s it. No setting to tweak here (again, only for Helios on Windows with a 6u21 pre build 7).
For non-Windows platform, you need to revert to the Sun proprietary option
The issue is based one a regression: JVM identification fails due to Oracle rebranding in java.exe, and triggered bug 319514 on Eclipse.
Andrew took care of Bug 320005 – [launcher]
--launcher.XXMaxPermSize: isSunVM should return true for Oracle, but that will be only for Helios 3.6.1.
Francis Upton, another Eclipse committer, reflects on the all situation.
Update u21b7, July, 27th:
Oracle have regressed the change for the next Java 6 release and won’t implement it again until JDK 7.
If you use jdk6u21 build 7, you can revert to the
--launcher.XXMaxPermSize (eclipse option) instead of
-XX:MaxPermSize (the non-standard option).
The auto-detection happening in the C launcher shim
eclipse.exe will still look for the “
Sun Microsystems” string, but with 6u21b7, it will now work – again.
For now, I still keep the
-XX:MaxPermSize version (because I have no idea when everybody will launch eclipse the right JDK).
Implicit `-startup` and `–launcher.library`
Contrary to the previous settings, the exact path for those modules is not set anymore, which is convenient since it can vary between different Eclipse 3.6.x releases:
- startup: If not specified, the executable will look in the plugins directory for the
org.eclipse.equinox.launcherbundle with the highest version.
- launcher.library: If not specified, the executable looks in the
pluginsdirectory for the appropriate
org.eclipse.equinox.launcher.[platform]fragment with the highest version and uses the shared library named
The JDK6 is now explicitly required to launch Eclipse:
-Dosgi.requiredJavaVersion = 1.6
This SO question reports a positive incidence for development on Mac OS.
The following options are part of some of the experimental options of the Sun JVM.
-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:+UseFastAccessorMethods
They have been reported in this blog post to potentially speed up Eclipse.
See all the JVM options here and also in the official Java Hotspot options page.
Note: the detailed list of those options reports that
UseFastAccessorMethods might be active by default.
See also “Update your JVM”:
As a reminder, G1 is the new garbage collector in preparation for the JDK 7, but already used in the version 6 release from u17.
Opening files in Eclipse from the command line
See the blog post from Andrew Niefer reporting this new option:
This tells the launcher that if it is called with a command line that only contains arguments that don’t start with “
-“, then those arguments should be treated as if they followed “
This is the kind of command line the launcher will receive on windows when you double click a file that is associated with eclipse, or you select files and choose “
Open With” or “
Send To” Eclipse.
Relative paths will be resolved first against the current working directory, and second against the eclipse program directory.
p2 and the Unsigned Dialog Prompt
If you are tired of this dialog box during the installation of your many plugins:
, add in your
I do want to say that security research supports the fact that less prompts are better.
People ignore things that pop up in the flow of something they want to get done.
For 3.6, we should not pop up warnings in the middle of the flow – no matter how much we simplify, people will just ignore them.
Instead, we should collect all the problems, do not install those bundles with problems, and instead bring the user back to a point in the workflow where they can fixup – add trust, configure security policy more loosely, etc. This is called ‘safe staging’.
Those options are not directly in the
eclipse.ini above, but can come in handy if needed.
The `user.home` issue on Windows7
When eclipse starts, it will read its keystore file (where passwords are kept), a file located in
If for some reason that
user.home doesn’t resolve itself properly to a full-fledge path, Eclipse won’t start.
Initially raised in this SO question, if you experience this, you need to redefine the keystore file to an explicit path (no more user.home to resolve at the start)
Add in your
Wait, there’s more than one setting file in Eclipse.
if you add to your
eclipse.ini the option:
, you enable the debug mode and Eclipse will look for another setting file: a
.options file where you can specify some OSGI options.
And that is great when you are adding new plugins through the dropins folder.
Add in your .options file the following settings, as described in this blog post “Dropins diagnosis“:
P2 will inform you what bundles were found in
dropins/folder, what request was generated, and what is the plan of installation. Maybe it is not detailed explanation of what actually happened, and what went wrong, but it should give you strong information about where to start:
- was your bundle in the plan?
- Was it installation problem (P2 fault)
- or maybe it is just not optimal to include your feature?
That comes from Bug 264924 – [reconciler] No diagnosis of dropins problems, which finally solves the following issue like:
Unzip eclipse-SDK-3.5M5-win32.zip to ..../eclipse Unzip mdt-ocl-SDK-1.3.0M5.zip to ..../eclipse/dropins/mdt-ocl-SDK-1.3.0M5
This is a problematic configuration since OCL depends on EMF which is missing.
3.5M5 provides no diagnosis of this problem.
No obvious problems. Nothing in Error Log.
Help / About / Plugindetails shows
org.eclipse.ocl.doc, but not
Help / About / Configurationdetails has no (diagnostic) mention of
Help / Installation / Information Installed Softwarehas no mention of
Where are the nice error markers?
See this blog post:
- In Galileo (aka Eclipse 3.5), JDT started resolving manifest classpath in libraries added to project’s build path. This worked whether the library was added to project’s build path directly or via a classpath container, such as the user library facility provided by JDT or one implemented by a third party.
- In Helios, this behavior was changed to exclude classpath containers from manifest classpath resolution.
That means some of your projects might no longer compile in Helios.
If you want to revert to Galileo behavior, add:
This SO question mentions a potential fix when not accessing to plugin update sites:
Mentioned here just in case it could help in your configuration.
JVM1.7×64 potential optimizations
This article reports:
For the record, the very fastest options I have found so far for my bench test with the 1.7 x64 JVM n Windows are:
-Xincgc -XX:-DontCompileHugeMethods -XX:MaxInlineSize=1024 -XX:FreqInlineSize=1024
But I am still working on it…