Just a short memo how to install Java 8 on Ubuntu.
Install:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java8-set-default
sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java8-set-default
Check java version:
java -version
Install Java 8 JDT in Eclipse
http://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_(BETA)