HOW DO I INSTALL JAVA ON LINUX

This article applies to:

• Platform(s): Red Hat Linux, SUSE Linux
• Browser(s): All Browsers
• Java version(s): 1.5.0, 6.0 

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Linux system requirements

See supported System Configurations for information about supported platforms, operating systems, desktop managers, and browsers.
You will also need a Pentium 166MHz or faster processor with a minimum of 75MB free disk space and a minimum of 32MB of RAM.


Follow these steps to download and install Java for Linux.

1. Download
2. Install
3. Enable and Configure

Download

1. Go to http://java.com and click on the Download button
2. There are two types of installation packages.
   
   • Linux self extracting binary file
     This file can be used to install Java in a location chosen by the user and can be installed by anyone (not only root users). As long as you are not root user, it cannot displace the system version of the Java platform suppled by Linux.
   • Linux RPM package
     Linux RPM (Redhat Package Manager) uses RPM to install Java. In order to use this method, you need to have RPM available on your system. Otherwise use the other option.
   
   Download the package that best suits your needs. You can download the file to any of the directories on your system.
3. Download and check the download file size to ensure that you have downloaded the full, uncorrupted software bundle.
   • Before you download the file, notice its byte size provided on the download page on the web site.
   • Once the download has completed, compare that file size to the size of the downloaded file to make sure they are equal.

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Install

Linux self extracting binary file

Linux RPM package

Note: The instructions below are for installing Java 6. If you're-installing another version, make sure you change the version number appropriately when you type the commands at the terminal.

To install the Linux (self-extracting) file

Follow these instructions:

1. Change the permission of the file you downloaded to be executable. Type:
   chmod a+x jre-6u-linux-i586.bin
2. Verify that you have permission to execute the file. Type:
   ls -l

3. Change to the directory in which you want to install. Type:
   cd
   For example, to install the software in the /usr/java/ directory, Type:
   cd /usr/java/
   
   Note about root access: To install Java in a system-wide location such as /usr/local, you must login as the root user to gain the necessary permissions. If you do not have root access, install the Java in your home directory or a subdirectory for which you have write permissions.

4. Run the self-extracting binary Type:
   ./jre-6u-linux-i586.bin
   
   The license agreement is displayed. Review the agreement. Press the spacebar to display the next page. At the end, enter yes to proceed with the installation.
   
5. Java is installed into its own directory. In this example, it is installed in the /usr/java/jre1.6.0_ directory. When the installation has completed, you will see the word Done.

6. Verify that the jre1.6.0_ sub-directory is listed under the current directory. Type:
   ls

The installation is now complete. Skip to the Enable and Configure section.

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To install the Linux RPM (self-extracting) file

Follow these instructions:

1. Become the root user by running the su command and entering the super-user password.
   At the terminal: Type:
   su
   Enter the root password.
2. Change to the directory in which you want to install. Type:
   cd
   For example, to install the software in the /usr/java/ directory, Type:
   cd /usr/java
   
   Note about root access: To install Java in a system-wide location such as/usr/local, you must login as the root user to gain the necessary permissions. If you do not have root access, install Java in your home directory or a subdirectory for which you have write permissions.
   
3. Change the permission of the file you downloaded to be executable. Type:
   chmod a+x jre-6u-linux-i586-rpm.bin
   
4. Start the installation process. Type:
   ./jre-6u-linux-i586-rpm.bin
   
   The license agreement is displayed. Review the agreement. Press the spacebar to display the next page. At the end, enter yes to proceed with the installation.
   
5. The installation file creates and runs the file jre-6-linux-i586.rpm in the current directory.

6. Verify that the jre1.6.0_ sub-directory is listed under the current directory. Type:
   ls

The installation is now complete. Go to the Enable and Configure section.

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Enable and Configure

Firefox or Mozilla

1. Create a symbolic link to the libjavaplugin.so file in the browser plugins directory
   • Go to the plugins sub-directory under the Firefox installation directory
     cd /plugins
     
   • Create the symbolic link
     ln -s /plugin/i386/
ns7/libjavaplugin_oji.so
     
     In the ln command line above, use ns7-gcc29 if Firefox was compiled with gcc2.9.
   
   If you install Firefox 1.5 or later, you can enable the Java Console menu item in the Tools menu. Change directories to the Firefox extensions directory, then unzip ffjcext.zip there.

   cd /usr/lib/firefox-1.4/extensions
unzip /usr/java/jre1.6.0/lib/deploy/ffjcext.zip

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   Example
   • If Firefox is installed at this directory:
     /usr/lib/firefox-1.4/
   • And if the Java is installed at this directory:
     /usr/java/jre1.6.0
   • Then type in the terminal window to go to the browser plug-in directory:
     cd /usr/lib/firefox-1.4/plugins
   • Enter the following command to create a symbolic link to the Java Plug-in for the Mozilla browser.
     ln -s /usr/java/jre1.6.0/plugin/i386/ns7/libjavaplugin_oji.so
   
   

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2. Start the Firefox browser, or restart it if it is already up.
   
   In Firefox, type about:plugins in the Location bar to confirm that the Java Plugin is loaded. If the version is Firefox 1.5 or later, click the Tools menu to confirm that Java Console is there

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Test Installation
To test that Java is installed and working properly on your computer, run this test applet.

Source : Java for Linux