Netbeans RCP: increasing JVM memory settings

This article explains how to increase memory limits for your Netbeans RCP application when using Ant to create a ZIP package or a Windows installer.

This article appeared originally at


Both ZIP package and Windows installer contain an executable that reads JVM and bootstrap settings from the etc/application_name.conf file. This file is copied from the laucher configuration template at netbeans-installation\harness\etc\app.conf. The default options contains all command line parameters passed to the executable. JVM parameters are prefixed by “-J”.

By default, this file has very tight memory settings (heap from 24 upto 64MB):

default_options="--branding ${branding.token} -J-Xms24m -J-Xmx64m"

Solution 1: Edit app.conf

Open netbeans-installation\harness\etc\app.conf and increase the -J-Xms and -J-Xmx parameters. However, this may require administrator priviledges if Netbeans IDE was installed into the application directory. The change will affect all application you build on the machine and will not get into your version control. You need to rememberto edit this file again on a fresh install.

Solution 2: Create your own app.conf

Create your own app.conf file within your application suite directory. Mention this file using the app.conf property within the nbproject/ file of your main application suite project.

# Main-Suite\nbproject\

My custom.conf looks like the original app.conf:

# Main-Suite\nbproject\custom.conf:
# ${HOME} will be replaced by user home directory according to platform
default_mac_userdir="${HOME}/Library/Application Support/${APPNAME}/${buildnumber}"

# options used by the launcher by default, can be overridden by explicit
# command line switches
default_options="--branding ${branding.token} -J-Xms128m -J-Xmx512m"

As the custom.conf resides inside the project configuration directory, it will be versioned by source control and used by every distribution build.


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