Moving from JDK 1.7 to JDK 1.8 on Ubuntu

I am on UBUNTU. JDK version currently installed is: java version "1.7.0_51" Java(TM) SE Runtime Environment (build 1.7.0_51-b13) Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode) the configuration being installed is: sudo update-alternatives --config java There is only one alternative in link group java (providing /usr/bin/java): /usr/lib/jvm/java-7-oracle/jre/bin/java I downloaded the latest tar.gz archive of JDK 1.8. How can I easily install JDK 1.8 from tar.gz overriding/uninstalling the JDK 1.7 currently installed? Or even without explicitly use the tar.gz.