Location of visualvm.conf in ubuntu for Java VisualVM

Sun Java 6 VisualVM
Sun Java 6 Monitoring & Management (VisualVM)
/usr/lib/jvm/java-6-sun-1.6.0.34/bin/jvisualvm

In doc we have <visualvm_installdir>\etc\visualvm.conf

so for linux/ubuntu it is:
$JAVA_HOME/lib/visualvm/etc/visualvm.conf

Example:
usr/lib/jvm/java-6-sun-1.6.0.34/lib/visualvm/etc/visualvm.conf


to avoid OutOfMemory on heap dump ivestigation you can change in visualvl.conf
for default values "-J-Xmx256m" to "-J-Xmx4G"