R.E.D.: Help Java install

Help about installing the Java Runtime Environment (JRE)
on 64 bits RedHat-based Linux (CentOS 5.4 & Fedora 12) distributions

Problems with Java? Use Pale Moon instead of Firefox or Chrome!

Opera 10.11, Firefox 3.5.11 and Chrome 5.0.375.125 under linux are used with Java applets to display molecular structures, charge values, atom names, force field atom types and molecular electrostatic potentials within Jmol.

Remove OpenJDK if installed:
rpm -e java-1.6.0-openjdk-plugin
rpm -e java-1.6.0-openjdk

Install the 64 bits version of Java ("jre-6u21-linux-amd64.rpm" is installed on our machines):
rpm -ivh jre-6u21-linux-amd64.rpm
rpm -ivh jre-6u21-linux-i586.rpm for 32 bits systems.

=> JRE is installed @ /usr/java/jre1.6.0_21
rpm -q jre provides "jre-1.6.0_21-fcs.x86_64" (and "jre-1.6.0_21-fcs.i586" for 32 bits systems)
rpm -q --filesbypkg jre provides more information.

On some other Linux distributions the path to the JRE installation might be /opt/java/jre-1.6...

In Opera Tools/Preferences.../Advanced/Content
Toggle on "Enable Java"
Java options:
Validate Java Path: /usr/java/jre1.6.0_21/lib/amd64 and /usr/java/jre1.6.0_21/plugin/i386 for 32 bits systems.

In Firefox Edit/Preferences/Content
Toggle on "Enable Java"

For Firefox & Chrome, create the following link (being "root"):
ln -s /usr/java/jre1.6.0_21/lib/amd64/libnpjp2.so /usr/lib64/mozilla/plugins/libnpjp2.so
ln -s /usr/java/jre1.6.0_21/lib/i386/ns7/libjavaplugin_oji.so /usr/lib/mozilla/plugins/libjavaplugin_oji.so for 32 bits systems.

Always restart your browser after installing JRE.

You can now test if JRE is well configured for the Browser you are currently using by clicking here.

The Java applets written for Jmol are displayed by Opera, Firefox & Chrome. Click here to look at an example.

Remarks:
- Opera 10.11 does not display the Jmol applets correctly under Fedora 12, while it works under CentOS 5.4. Upgrading to Opera 10.60 solved the problem.
- On CentOS and Fedora, we found Opera quite slow to display Java applets, while Chrome (and Firefox) are very fast...