Uninstall JDK rpm to reinstall

What's that packages name?

When you don't know the name of a specific RPM to uninstall you can search for it like so using the command rpm.

$ rpm -aq | grep -i jdk
java-1.7.0-openjdk-devel-1.7.0.60-2.4.4.0.fc19.x86_64
jdk-1.7.0_45-fcs.x86_64
java-1.7.0-openjdk-1.7.0.60-2.4.4.0.fc19.x86_64

Based on the above output I have 2 versions of Java installed. The official Oracler version, jdk-1.7.0_45 and the IceTea version aka. Open JDK, java-1.7.0-openjdk-1.7.0.60-2.4.4.0.

Uninstalling

To uninstall the official version of Java (JDK) you could use the following commands, yum or rpm:

yum

$ sudo yum remove jdk
[sudo] password for saml: 
Loaded plugins: auto-update-debuginfo, changelog, langpacks, refresh-packagekit
Resolving Dependencies
--> Running transaction check
---> Package jdk.x86_64 2000:1.7.0_45-fcs will be erased
--> Finished Dependency Resolution

Dependencies Resolved

=====================================================================================================================
 Package              Arch                    Version                               Repository                  Size
=====================================================================================================================
Removing:
 jdk                  x86_64                  2000:1.7.0_45-fcs                     installed                  193 M

Transaction Summary
=====================================================================================================================
Remove  1 Package

Installed size: 193 M
...

rpm

$ sudo rpm -e jdk

I would recommend always trying to use yum if you can, it does dependency checks that rpm does not.

Search pre-installed JAVA:

$ rpm -qa | grep java
javapackages-tools-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.151-5.b12.el7_4.x86_64

Remove using following command:

rpm -e java-1.8.0-openjdk-headless-1.8.0.151-5.b12.el7_4.x86_64
rpm -e javapackages-tools-3.4.1-11.el7.noarch