The easiest way would be to download and install the JDK version you want
from Oracle's website. They offer RPM packages which should work in the VM,
or a tarball that you can extract yourself anywhere you like. Once it's
installed, make a note of the directory it installed to: the RPMs will
install under /usr/lib/jvm or /usr/java or something like that. The
directory will include the version in the name, and should have a /bin/
directory underneath it. With that directory, you'll want to update the
value of JAVA_HOME in /etc/profile and restart any shell sessions you have
open. If you want CDH to use that JDK as well, export JAVA_HOME in
/etc/default/bigtop-utils.