JAVA 8 su Ubuntu

Aggiungere il repository e installare java 8 

$ sudo add-apt-repository ppa:webupd8team/java
$ sudo apt-get update
$ sudo apt-get install oracle-java8-installer

Verificare la versione:

$ java -version

java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)

Impostare java environment:

$ sudo apt-get install oracle-java8-set-default

Verificare tutte le versioni di JAVA presenti

$ sudo update-alternatives --config java

Eliminare tutte le versioni di JAVA

1. Rimuovere tutti i pacchetti:

sudo apt-get update
apt-cache search java | awk '{print($1)}' | grep -E -e '^(ia32-)?(sun|oracle)-java' -e '^openjdk-' -e '^icedtea' -e '^(default|gcj)-j(re|dk)' -e '^gcj-(.*)-j(re|dk)' -e 'java-common' | xargs sudo apt-get -y remove
sudo apt-get -y autoremove

2. Purge file configurazione:

dpkg -l | grep ^rc | awk '{print($2)}' | xargs sudo apt-get -y purge 

3. Rimuovere file di configurazione e cache directory:

sudo bash -c 'ls -d /home/*/.java' | xargs sudo rm -rf

4. Rimuovere nanualmente JVM installate:

sudo rm -rf /usr/lib/jvm/*

5. Rimuovere tutti la java entry:

for g in ControlPanel java java_vm javaws jcontrol jexec keytool mozilla-javaplugin.so orbd pack200 policytool rmid rmiregistry servertool tnameserv unpack200 appletviewer apt extcheck HtmlConverter idlj jar jarsigner javac javadoc javah javap jconsole jdb jhat jinfo jmap jps jrunscript jsadebugd jstack jstat jstatd native2ascii rmic schemagen serialver wsgen wsimport xjc xulrunner-1.9-javaplugin.so; do sudo update-alternatives --remove-all $g; done

6. Cercare le eventuali possibili java directory:

sudo updatedb
sudo locate -b '\pack200'