Install and configure the Java Development Kit (JDK) on your host machine. You need to know the path to your JDK installation directory later in this installation procedure.
Download JDK here : http://www.oracle.com/technetwork/java/javase/downloads/index.html
Or, you can use the one pre-installed with Weblogic installation explained in step 2 (to follow).
To find the required JDK version and the required versions of other supporting software, refer to the Oracle ATG Commerce Supported Environments Matrix document in the My Oracle Support knowledge base.