How to uninstall built-in OpenJDK in CentOS

Check whether JDK is installed in Linux.

The installed CentOS comes with OpenJdk and uses the java-version command. The following information is displayed:

Java version "1.6.0 & Prime;
OpenJDK Runtime Environment (build 1.6.0-b09)
OpenJDK 64-Bit Server VM (build 1.6.0-b09, mixed mode)
It is best to uninstall openjdk first and install the jdk of sun.

Check rpm-qa | grep java first

The following information is displayed:

Java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5
Uninstall open jdk
Rpm-e-nodeps java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Rpm-e-nodeps java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5

There are other commands

Rpm-qa | grep gcj
Rpm-qa | grep jdk

If openjdk source cannot be found, you can uninstall it like this.

Yum-y remove java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Yum-y remove java java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5
1. # rpm-qa | grep jdk to view jdk information or directly execute or rpm-q jdk or java-version
2. # rpm-qa | grep gcj confirm the gcj version number
3, # yum-y remove java-1.4.2-gcj-compat uninstall gcj

After installation, we still need to use jdk. So let's install a sun jdk.

Download Sun's JDK. I downloaded

Jdk-6u37-linux-i586-rpm.bin

For a 64-bit system, download:

Jdk-6u37-linux-x64-rpm.bin

And other 64-bit dedicated packages

 

Create a java directory under the/usr directory and put the downloaded file under the/usr/java Directory

Change the file to an executable file (chmod 777 ):

[Root @ dc-01 java] # chmod 777 jdk-6u37-linux-i586-rpm.bin

Then execute this file to install it:

[Root @ dc-01 java] #./jdk-6u37-linux-i586-rpm.bin
 
Press Enter.

Done appears.
 

The installation is now complete.

 

Configure JDK:

Vi/etc/profile open the profile file and add the following at the end of the profile file:

JAVA_HOME =/usr/java/jdk1.6.0 _ 37
PATH = $ JAVA_HOME/bin: $ PATH
CLASSPATH =.: $ JAVA_HOME/lib/dt. jar: $ JAVA_HOME/lib/tools. jar
Export JAVA_HOME
Export PATH
Export CLASSPATH
 
Save and close the profile file, and run the source/etc/profile command to make the modification take effect.

Run java-version to check the java version:

[Root @ dc-01 java] # java-version

Java version "1.6.0 _ 37"
Java (TM) SE Runtime Environment (build 1.6.0 _ 37-b06)
Java HotSpot (TM) Client VM (build between 12-b01, mixed mode, sharing)
[Root @ dc-01 java] #
========================================================== ==========

 

So far, the entire installation process is complete.