my netbeans.conf file

netbeans.conf

# ${HOME} will be replaced by JVM user.home system property
netbeans_default_userdir="${HOME}/.netbeans/6.9"

# Options used by NetBeans launcher by default, can be overridden by explicit
# command line switches:
netbeans_default_options="-J-client -J-Xss2m -J-Xms32m -J-Xmx384m -J-XX:PermSize=32m -J-XX:MaxPermSize=200m -J-Xverify:none -J-XX:CompileThreshold=100 -XX:+CompressedOOPS -XX:+AggressiveOpts -XX:+TieredCompilation -XX:+DoEscapeAnalysis -XX:+UseConcMarkSweepGC -J-XX:+CMSClassUnloadingEnabled -J-XX:+CMSPermGenSweepingEnabled -J-Dapple.laf.useScreenMenuBar=true --laf com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel -J-Dsun.java2d.noddraw=true -J-Dswing.aatext=true -J-Dawt.useSystemAAFontSettings=lcd_hrgb -J-Dscala.home=/home/stream/apps/scala"
# Note that a default -Xmx is selected for you automatically.
# You can find this value in var/log/messages.log file in your userdir.
# The automatically selected value can be overridden by specifying -J-Xmx here
# or on the command line.

# If you specify the heap size (-Xmx) explicitely, you may also want to enable
# Concurrent Mark & Sweep garbage collector. In such case add the following
# options to the netbeans_default_options:
# -J-XX:+UseConcMarkSweepGC -J-XX:+CMSClassUnloadingEnabled -J-XX:+CMSPermGenSweepingEnabled
# (see http://wiki.netbeans.org/wiki/view/FaqGCPauses)

# Default location of JDK, can be overridden by using --jdkhome <dir>:
netbeans_jdkhome="/usr/lib/jvm/java"

# Additional module clusters, using ${path.separator} (';' on Windows or ':' on Unix):
#netbeans_extraclusters="/absolute/path/to/cluster1:/absolute/path/to/cluster2"

# If you have some problems with detect of proxy settings, you may want to enable
# detect the proxy settings provided by JDK5 or higher.
# In such case add -J-Djava.net.useSystemProxies=true to the netbeans_default_options.

Well, I think you should change netbeans_jdkhome="/usr/lib/jvm/java" by netbeans_jdkhome=$JDK_HOME and add to $HOME/.profile this line export JDK_HOME="/usr/lib/jvm/java"

What's the right location for the user's netbeans.conf?