Java: Difference between revisions

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==What is Java?==
==What is Java?==
Java is a fully-fledged programming language which is used to create software applications and programs of arbitrary complexity. These programs can also be embedded in web pages, in which case they are called ‘applets’. Websites will often provide games in the form of applets.
[[wikipedia:Java programming language | Java]] is a fully-fledged programming language which is used to create software applications and programs of arbitrary complexity. These programs can also be embedded in web pages, in which case they are called ‘applets’. Websites will often provide games in the form of applets.


For your browser to display applets, you need to install the Java Runtime Environment (JRE, or just ‘Java’), and either tell it where to find your browser or tell your browser where to find it! With the latest releases of the JRE and modern browsers, this should happen automatically.
For your browser to display applets, you need to install the Java Runtime Environment (JRE, or just ‘Java’), and either tell it where to find your browser or tell your browser where to find it! With the latest releases of the JRE and modern browsers, this should happen automatically.

Revision as of 14:56, 27 February 2005

What is Java?

Java is a fully-fledged programming language which is used to create software applications and programs of arbitrary complexity. These programs can also be embedded in web pages, in which case they are called ‘applets’. Websites will often provide games in the form of applets.

For your browser to display applets, you need to install the Java Runtime Environment (JRE, or just ‘Java’), and either tell it where to find your browser or tell your browser where to find it! With the latest releases of the JRE and modern browsers, this should happen automatically.

Please note that Java is not JavaScript!

Installing Java

There is currently a bug in Firefox: if Java is installed but has been disabled in the Firefox options, Firefox will prompt you to install Java again. To check that Java is not disabled in Firefox, go to "Tools -> Options -> Web Features". Once you have enabled Java in Firefox, you must restart the browser. Then visit the test page below to test if Java is working. If not, continue with these steps.

If you are upgrading from a previous version of Java, you should first remove any old Java files from the plugins folder (or use the appropriate uninstall procedure for your operating system).

On Windows

If you are upgrading from a previous version of Java, you should first remove any old Java versions by using the add-remove applet in Control Panel.

  1. Download Java here. When installing Java, if you are given the option of a "Custom Install", take it. If you are then asked to choose which browsers you wish to support, ensure that you choose to enable Java for Mozilla and Netscape browsers.
  2. Test whether your installation is working by visiting the test page below.
  3. If Java is not working, open the Java Plug-in from the Windows Control Panel, find which version of the Java Control Panel you are running (by visiting the "About" tab or button). Then proceed as follows:

For new Java (Java Control Panel 1.5 for JRE 5.0, and above)

This version of Java Control Panel no longer allows the user to choose which browsers the JRE should be made visible to. (This seems bizarre, given that on the manual custom installation of JRE 5.0 asks you which browsers to support; if you can’t change this setting afterwards, why not just automatically support all browsers?)

If you originally installed Java directly through your browser, you could try downloading the manual installer from the link provided above and then perform a manual, custom install.

For older Java (Java Control Panel 1.4.x and below)

  1. Open the "Java Plug-in" item from the Windows Control Panel, and find the panel or dialog where you can configure which browsers Java makes itself visible to. Attempt to activate Java for Netscape and Mozilla if these options are not already ticked. (You may be told that you do not have these browsers; if so, skip the next step.)
  2. Test again whether your installation is working by visiting the test page below.
  3. Installing Java requires registry entries to locate firefox. The Firefox installer should create them. However, zip builds and some installer versions fail to create a registry entry required by Java. Save this registry patch to your desktop. Double-click on it, or right-click it and select "Merge".
  4. Test again whether your installation is working by visiting the test page below. Hopefully it is!

On Linux

  1. Download the Linux version of the Java SDK.
  2. When the download is finished, execute the .bin file as root and follow the prompts.
  3. When the installation has completed, run this command in the plugins directory of your Firefox installation:
    ln -s /your_path_here/java/j2re1.5.0/plugin/i386/ns7/libjavaplugin_oji.so libjavaplugin_oji.so

On Solaris Intel

  1. Install the Solaris Intel version of the Java JRE or SDK.
  2. When the installation has completed, run this command in the plugins directory of your Firefox installation:
    ln -s /your_path_here/jre/plugin/i386/ns610/libjavaplugin_oji.so .

External Resources