How to completely uninstall Java

Langkah pertama,

Remove all the Java related packages

dpkg-query -W -f='${binary:Package}\n' | 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

Langkah kedua : purge confiq files :

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

langkah ketiga : Remove Java config and cache directory

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

langkah 4 : Remove manually installed JVMs:

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

langkah 6 : Remove Java entries, if there is still any, from the alternatives:

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

langkah 7 :Search for possible remaining Java directories:

sudo updatedb
sudo locate -b '\pack200'

jika masih ada lagi output seperti /xxxx/xxxx/xxxx/bin/pack200
sila remove dengan rm -rf, seperti ini.

sudo rm -rf /xxxx/xxxx/xxxx

untuk pastikan yang semua java tu sudah tiada, boleh periksa dengan

java -version atau javac -version

sepatutnya akan kelihatan sebegini.