Completely uninstall and reinstall OpenJDK
I searched askubuntu and tried the suggestions but failed .I try this question:How to completely uninstall Java?
1.I run sudo apt-cache search openjdk get the following:
openjdk-6-dbg - Java runtime based on OpenJDK (debugging symbols)
openjdk-6-demo - Java runtime based on OpenJDK (demos and examples)
openjdk-6-doc - OpenJDK Development Kit (JDK) documentation
openjdk-6-jdk - OpenJDK Development Kit (JDK)
openjdk-6-jre - OpenJDK Java runtime, using Hotspot JIT
openjdk-6-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-6-jre-lib - OpenJDK Java runtime (architecture independent libraries)
openjdk-6-source - OpenJDK Development Kit (JDK) source files
icedtea-7-jre-jamvm - Alternative JVM for OpenJDK, using JamVM
openjdk-6-jre-zero - Alternative JVM for OpenJDK, using Zero/Shark
openjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols)
openjdk-7-demo - Java runtime based on OpenJDK (demos and examples)
openjdk-7-doc - OpenJDK Development Kit (JDK) documentation
openjdk-7-jdk - OpenJDK Development Kit (JDK)
openjdk-7-jre - OpenJDK Java runtime, using Hotspot JIT
openjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries)
openjdk-7-jre-zero - Alternative JVM for OpenJDK, using Zero/Shark
openjdk-7-source - OpenJDK Development Kit (JDK) source files
2.run sudo apt-get remove openjdk get the following:Reading package lists... Done
Building dependency tree
Reading state information... Done
Package openjdk-7-jdk is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 182 not upgraded.
3 Answers
You cannot remove OpenJDK 7 because it is not installed. If you are trying to remove OpenJDK 6, try sudo apt-get remove openjdk-6-jdk, or sudo apt-get remove default-jdk.
apt-cache search only shows you available packages, not the packages you have installed. For that, try sudo dpkg --list; sudo dpkg --list | grep -i jdk will show you any JDK-related packages installed on your system.
Run this command, which lets you choose which Java installation to make the default:
sudo update-alternatives --config javaThere are 2 choices for the alternative java (providing /usr/bin/java). Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java 1061 auto mode 1 /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java 1061 manual mode 2 /usr/lib/jvm/java-7-oracle/jre/bin/java 1 manual modeRecently, I tried to reinstall Java completely. This may help you to remove it:
sudo apt-get remove openjdk*
sudo apt-get cleanThen, if you want, install Java:
sudo apt-get install openjdk-8-jdkFollowing these steps helped me to solve my problem.
