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Wednesday, June 6, 2007

JDeveloper Tips #2: Fine-tuning the configuration

by Eduardo Rodrigues
Yet another great tip - this one is specially directed to those using JDeveloper on Windows.

It may seem strange but the amount of programmers aware of the possibility of customizing JDev's initialization settings isn't so big as you may expect. Many don't even know about the existence of a configuration file. Well, there is a configuration file and it's located at %JDEV_HOME%\jdev\bin\jdev.conf (%JDEV_HOME% being the directory where you've installed JDeveloper). If you open this file you'll see a great number of options, properties, etc. The guys at Oracle did their job and commented on every one, so it won't be difficult to figure out their purpose.

Having said that, I'd like to share with you some lessons learned through my own experience that have certainly made my work with JDeveloper much smoother:

#
# This is optional but it's always
# interesting to keep your JDK up to date
# as long you stay in version 1.5
#
SetJavaHome C:\Program Files\Java\jdk1.5.0_12

#
# Always a good idea to set your User Home
# appropriately. To do so, you must
# configure an environment variable in
# the operating system and set its value
# with the desired path
# (i.e. JDEV_USER_HOME=D:\myWork\myJDevProjs).
# Then you must set the option bellow with
# the variable's name.
#
# You'll notice that when you change
# the user home directory, JDev will ask
# you if you want to migrate from a
# previous version. That's because it
# expects to find a "system" subdirectory.
# If you don't wanna loose all your config
# I recommend that you copy the "system"
# folder from its previous location
# (%JDEV_HOME%\jdev\system is the default) to
# your new JDEV_USER_HOME before restarting
# JDev.
#
SetUserHomeVariable JDEV_USER_HOME

#
# Set VFS_ENABLE to true if your
# projects contain a large number of files.
# You should use this specially if
# you're using a versioning system.
#
AddVMOption -DVFS_ENABLE=true

#
# Try to make JDev always fit in your available
# physical memory.
# I really don't recommend setting the maximum
# heap size to less than 512M but sometimes it's
# better doing this than having to get along with
# unpleasant Windows memory swapping.
#
# Just a reminder: this option does not establish
# an upper limit for the total memory allocated
# by the JVM. It limits only the heap area.
#
AddVMOption -Xmx512M

#
# Use these options bellow ONLY IF you're
# running JDeveloper on a multi-processor or
# multi-core machine.
#
# These options are designed to optimize the pause
# time for the hotspot VM.
# These options are ignored by ojvm with an
# information message.
#
AddVMOption -XX:+UseConcMarkSweepGC
AddVMOption -XX:+UseParNewGC
AddVMOption -XX:+CMSIncrementalMode
AddVMOption -XX:+CMSIncrementalPacing
AddVMOption -XX:CMSIncrementalDutyCycleMin=0
AddVMOption -XX:CMSIncrementalDutyCycle=10

#
# On a multi-processor or multi-core machine you
# may uncomment this option in order to
# limit CPU consumption by Oracle JVM client.
#
# AddVMOption -Xsinglecpu

#
# This option isn't really documented but
# it's really cool!
# Use this to prevent Windows from paging JDev's memory
# when you minimize it.
# This option should have the same effect as
# the KeepResident plug-in with the advantage
# of being a built-in feature in Sun's JVM 5.
#
AddVMOption -Dsun.awt.keepWorkingSetOnMinimize=true

3 comments:

Anonymous said...

Hi, is very interesting your post, but how I do configuration the jvm in JDeveloper 11?
thanks!

Fábio Saraiva de Souza said...

Hello anonymous,
The same configuration file exists in JDeveloper 11. By the way, this option: "AddVMOption -Dsun.awt.keepWorkingSetOnMinimize=true"
is already there!

Cheers,
Fábio

Valery said...

Hello.
In fact Jdeveloper 11g does not start at all with AddVMOption -XX:+UseConcMarkSweepGC
AddVMOption -XX:+UseParNewGC
AddVMOption -XX:+CMSIncrementalMode
AddVMOption -XX:+CMSIncrementalPacing
AddVMOption -XX:CMSIncrementalDutyCycleMin=0
AddVMOption -XX:CMSIncrementalDutyCycle=10 parameters as you mentioned above (JVM 1.6.0_23 and win7-32). The instance of jvm cannot be created.
But it could be used the following parameters that work fine: AddVMOption -XX:+UseParallelGC
AddVMOption -XX:ParallelGCThreads=4 (I have four cores on my desktop)
AddVMOption -Xss128k

Regards, valery.