If like me you run in to issue when using OpenJDK, my issues come from it’s memory problems when you’re allocating and using large amounts of memory - mostly for Solr where we’re concerned but obviously I’d switch for other high memory usage instances too.
So without further ado, lets get the installation going.
You’ll need Debian’s “add-apt-repository”, on servers this doesn’t usually come by default so we’ll need to install it.
sudo apt-get install python-software-properties
Next we need to add Java’s PPA.
sudo add-apt-repository ppa:sun-java-community-team/sun-java6
Once this is done we’ll need to update our apt caches and install Java 6.
sudo apt-get install sun-java6-jdk
Now that this is installed we should get the Java version, remember it for future.
java -version
You’ll get something like this
java version "1.6.0_20" OpenJDK Runtime Environment (IcedTea6 1.9.9) (6b20-1.9.9-0ubuntu1~10.04.2)
OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode)
Next we update our alternatives to switch OpenJDK with Sun’s Java.
sudo update-java-alternatives -s java-6-sun
And finally we’ll confirm the change is made by comparing the new Java version against the one from before
java -version
You should see something similar to this.
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot(TM) 64-Bit Server VM (build 17.0-b16, mixed mode)
Tomcat 6
To make Tomcat use this version of Java we’ll need to change JAVA_HOME.
Open up /etc/default/tomcat6 for editing, you’ll need to open this using sudo or as root.
Scroll down, you’ll see JAVA_HOME is set, it may be commented out so edit it to look like the line below.
JAVA_HOME=/usr/lib/jvm/java-6-sun
And restart Tomcat.
sudo /etc/init.d/tomcat6 restart
