Switching JDKs for JDeveloper/WLS Explained
By Oliver Steinmeier on May 08, 2013
During the install of JDeveloper, you'll be asked to choose between "Complete" and "Custom" install type. Choose "Custom" as this gives you the option of configuring JDeveloper/WLS with a JDK other than the one that's included with the installer. Of course, this means that you should actually install the 64 bit JDK prior to running the JDeveloper installer. You can find the 64-bit JDK (e.g., version 1.6.0_24) here.
Choose Custom Install to use an already installed 64-bit JDK
In the JDK Section dialog, be sure to uncheck the bundled JDK and use the "Browse..." button to add the 64-bit JDK you want to use.
Changing the JDK to be used by JDeveloper/WLS
Then proceed with all the default options.
You can verify that JDeveloper is using the proper JDK by checking the jdev.conf file in %MW_HOME%/jdeveloper/jdev/bin. You can also use the Help -> About dialog; the JDK is shown in the Properties tab. Look for java.version and java.vm.name.
When you start the integrated WebLogic Server, it will display the Java version number it uses in the Console log pane:
starting weblogic with Java version:
java version "1.6.0_31"
Java(TM) SE Runtime Environment (build 1.6.0_31-b05)
Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode
If you have a standalone WLS configured, it already uses a 64-bit version of the JRockit JVM, so there is no change required for it.