Java is a programming language that can be used on almost any device, whether it be a computer, PDA, or cell phone. Currently most computers have some form of Java installed, also there are PDAs and cell phones that have Java. It is popular for use on the web, such as with the Broadband Reports speed and tweak tests. For a more in depth answer check out the What is Java Technology? webpage.

You can download the correct Java Runtime Environment from http://www.java.com.

it is so that you can see any errors that happen when java applets run.. sometimes the error gives you a clue what can be done to fix something, but they are 99% of the time not any help unless you are the developer of the applet.

Credit for this answer goes to Justin...

JavaScript is not Java! In order to get JavaScript to work you need to go into the properties windows of whatever browser you are using and enable it.

For Mozilla Firebird this is in Tools->Options then click on Web Content in the side bar. There you will see two check boxes, one to enable Java and one to enable JavaScript.

For IE 5.x+ click on Tools->Internet Options then on the Security tab. From here click on the Custom Level button and in the window that pops up you will need to scroll till you come to almost the end of the list, this will be where the scripting options will be. For Highest Security you can disable, medium security you can have it prompt you for whether or not you want to run scripting, and for low security you can allow IE to run JavaScript (and other types of scripts) wherever and whenever it comes across them.

In Opera go to Tools (for Opera 7.5x) or File (for Opera 7.2x)->Quick Preferences and make sure "Enable Javascript" is checked.

After downloading the installation file, uninstall any previous versions of Java from the Add/Remove Programs applet in the Control Panel. Then double click the install file and it should do most of the work itself.

1. Download the latest Java Runtime Environment from the Java Website and install it
2. Go into C:\Program Files\Java\j2re1.4.0\bin or wherever you installed Java.
3. Copy the file NPOJI610.dll (or NPOJI600.dll depending on the version of Java you downloaded)
4. Go to C:\Program Files\mozilla.org\Mozilla\Plugins or wherever you installed Mozilla and paste the file there.
5. Restart Mozilla and Java should be working.

With the introduction of service pack 1 you can choose which version of Java to use by going to the Set Program and Access Defaults dialog from the top of the start menu. Just click the custom section and you can change the JVM your using from there...

It is included in Windows XP Service Pack 1. A more detailed description can be found in the Microsoft Help forum XP FAQ -- HELP! I don't have Java? What do I do? How do I get it? (#4497)

Per this F.A.Q. on the Mozilla Firebird site »texturizer.net/firebird/ ··· tml#q2.2 there are two ways to get Java to work with Mozilla Firebird.

1) The easiest (that the people at Mozilla say) is to download the unsupported installer from »seb.mozdev.org/firebird and then install the XPInstall for java found here »java.sun.com/getjava/manual.html

2) Not so easy, however not too difficult, this method involves downloading a Reg file found here: »plugindoc.mozdev.org/res ··· -fix.reg then installing the JRE, which can be downloaded from here java.sun.com if needed, or if Java is already installed the F.A.Q. says to simply restart the Mozilla Firebird Browser.

NOTE: If neither of these solutions work, for one reason or another try using the 1.4.1_05 version of the JRE as this version does not require the registry keys that 1.4.2 does.

The installation instructions for installing Java on Linux can be found at here.

If you have Netscape 4.xx then simply set NPX_PLUGIN_PATH environment variable to the directory containing the javaplugin.so file for ns4. This will vary depending on where you installed Java.

If you have Netscape 6.0x then you can use the regxpcom tool to do it. Just cd to your netscape directory then

regxpcom [JRE]/plugin/i386/ns600/libjavaplugin_oji140.so

where [JRE] is where you installed Java. If you have Netscape 6.10 or greater than replace ns600 with ns610 in the command.

Copy the libjavaplugin_oji140.so from [JRE]/plugin/i386/ns610/libjavaplugin_oji140.so to your [Mozilla]/plugins directory.

(where [JRE] is where you installed Java and [Mozilla] is where you installed Mozilla)

A common problem with Mozilla and Java Applets on the web is that when you click a button it doesn't get pushed. Sun is aware of the problem. Right now the temperary fix is to use the spacebar to click the button while your cursor is over the button you want to push.

In the commandline you have to type (as root and any user that wants to use Java)

PATH=$PATH:[path to Java]/bin

where [path to Java] is where you installed Java. You may also have to do

export PATH

Well there are two ways to do it. The easiest way is to:

emerge mozilla


and then make the symlink from /opt/blackdown-jre-1.3.1/plugin/i386/mozilla/javaplugin_oji.so to /usr/local/mozilla/plugins. It should then work. However if you want to have the latest mozilla build then do...


emerge -o mozilla


and download the nightly build from the Mozilla website. Then make the symlink. The emerge -o mozilla will download all the dependencies needed including Java, to run Mozilla. Finally inject mozilla into your portage tree so that portage knows you installed it.


emerge -i net-www/mozilla-1.0.1-r3


and you should be all set.

This will not work in Gentoo 1.4-RC1