Java on ubuntu

How to find out version:

update-java-alternatives -l java -showversion java -version

How to install java8 sudo add-apt-repository ppa:openjdk-r/ppa sudo apt-get update sudo apt-get install openjdk-8-jdk sudo update-alternatives --config java sudo update-alternatives --config javac And from oracle $ sudo add-apt-repository ppa:webupd8team/java $ sudo apt-get update $ sudo apt-get install oracle-java8-installer How to remove

sudo apt-get purge openjdk-7-*

How to install: sudo apt-get install openjdk-7-jre or sudo apt-get install openjdk-7-jdk