We have two Java 2 SDK's installed in /opt/j2sdk. Decide on which one you would like to use as the default. For example if you decide to use the source compiled J2SDK, do the following: ln -nsf j2sdk-&j2sdk-src-version; /opt/j2sdk/j2sdk Add the following lines to your shell startup file (e.g. /etc/profile). export JAVA_HOME=/opt/j2sdk/j2sdk export PATH=$PATH:$JAVA_HOME/bin Add $JAVA_HOME/man to your MANPATH variable or to /etc/man.conf The Java plugin is in the directory $JAVA_HOME/jre/plugin/i?86/ns610/. Make a symbolic link to the file in that directory from your plugins directory. When compiling packages, the CLASSPATH environment variable is used JDK to locate classes at compile-time and run-time. It is tedious to add all the classes used to the CLASSPATH manually. You may add the following lines to your shell startup file to set CLASSPATH automatically to include all JAR files in a specified directory, which in the example below is /usr/lib/auto-java-classpath. AUTO_CLASSPATH_DIR=/usr/lib/auto-java-classpath if [ -z $CLASSPATH ] then CLASSPATH=.:$AUTO_CLASSPATH_DIR else CLASSPATH=$CLASSPATH:.:$AUTO_CLASSPATH_DIR fi for i in $(ls $AUTO_CLASSPATH_DIR/*.jar 2>/dev/null) do CLASSPATH=$CLASSPATH:$i done