Instalar java jdk en debian 8

Uncompress archive

Now you uncompress and move the whole uncompressed folder to /opt (optional) directory.

tar -xzvf /root/jdk-7u79-linux-x64.tar.gz
mv jdk1.7.0_79 /opt
cd /opt/jdk1.7.0_79

Install and register binaries

This step registers the downloaded version of Java as an alternative, and switches it to be used as the default:

update-alternatives --install /usr/bin/java java /opt/jdk1.7.0_79/bin/java 1

update-alternatives --install /usr/bin/javac javac /opt/jdk1.7.0_79/bin/javac 1

update-alternatives --install /usr/lib/mozilla/plugins/libjavaplugin.so mozilla-javaplugin.so /opt/jdk1.7.0_79/jre/lib/amd64/libnpjp2.so 1

update-alternatives --set java /opt/jdk1.7.0_79/bin/java

update-alternatives --set javac /opt/jdk1.7.0_79/bin/javac

update-alternatives --set mozilla-javaplugin.so /opt/jdk1.7.0_79/jre/lib/amd64/libnpjp2.so

Testing your installation

First of all, close your browser and re-open. You won’t believe how many users actually forgets to do this step and later complains Java ain’t working. I’d advise to bookmark this site to be able to reopen these instructions quickly, or simply copy these into a leafpad / vi / text-editor.
To check the version of Java you are now running

java -version