Wednesday, April 27, 2016

How to install or upgrade Java in Linux (Updated)

In this blog post I show how to install or update Java from Oracle on a Linux server. Many Linux distros use the OpenJDK version of Java in their operating systems and in their repository. Although the instructions below will still work to install OpenJDK, the focus is on Oracle's version of Java.

When using the Java provided by Oracle, you can download it from Oracle's website or from java.com. From there they give you a choice of downloading rpm or tar files. I prefer to use Red Hat Package Manager (RPM) files instead of the tar files when installing any program.

You can download Java here: www.java.com

Find Java on the system.
root@earth> find / -name java -type f
/usr/java/jre1.7.0_101/bin/java

Note - If you use which or java -version commands to find Java on your system. This will only show your the system's main java. You may have additional versions installed.

Now take each line of output and paste it at the end of the rpm -qf command. This gives you the name of the rpm package that installed that instance of Java.

root@earth> rpm -qf   /usr/java/jre1.7.0_101/bin/java
jre-1.7.0_101s

If the Java found on the system was not installed via a package, then Java was installed via a tar file. At this point you must decide whether to install the new version of Java with an rpm or a tar file. I recommend the use of the rpm packages to install any programs. If you are installing with a rpm then go to the section titled Installing Java using RPM. If you are use the tar file then skip to the section titled Install Java using a tar file.

Installing Java using RPM
The rpm command can either update an existing package or install a new one.

The documentation on the Java website says to remove/uninstall the old version of Java and then install the new one. I prefer to install or upgrade though. This is because if there are any symlinks or application settings that use the systems' Java, will be updated to use the newer Java. Then you can remove the old version if needed after the fact. Otherwise you would have to recreate these items after the install.

Updating Java using RPM 
If you update Java as shown below then you will not need to remove the old version. Unless you are installing a different version of Java. For exampe If you have Java 7 installed and then you install Java 8
root@earth> rpm  -Uvh   jre-7u111-linux-x64.rpm

You can alternately install Java instead.
root@earth> rpm  -ivh   jre-7u111-linux-x64.rpm

Uninstall the old package.
Take the output from the last command and use the rpm command with the -e option to remove the package.
root@earth> rpm -e  jre-1.7.0_65cs

Note- Do not run the above command for java that is part of an application. If the file was in /usr/bin/ you should be fine.

Install Java using a tar file
Change directory to where Java is going to be installed. Usually it will be /user/java.
root@earth> cd  /usr/java

Note - If your upgrading Java with a tar file, it is advised to backup the old installation and to remove the previous version. If the old version was installed via a tar then remove the directory. If it was installed with a rpm file use the rpm or yum command to remove the package. 

Move the tar file to /usr/java and unpack the tarball to install Java
root@earth> tar  zxvf   jre-7u111-linux-i586.tar.gz

Delete the tar file after you test Java and your done.

Reference:
Java.com

Related posts on this Blog
How to install or upgrade Java in Linux
How to install Java 7 & 8 on Solaris
Access the Java Control Panel
Updating Java on Solaris

If you have any questions or comments please post them below.

No comments:

Post a Comment