Java Plug-in Overview

Introduction

Java Plug-in software from Sun Microsystems Inc. enables web page authors to direct Java applets or JavaBeans components on their intranet web pages to run using Sun's Java 2 Runtime Environment, Standard Edition (JRE), instead of the browser's default runtime. This release provides support for Microsoft Internet Explorer and Netscape Navigator on various Win32 platforms. Java Plug-in delivers full Java 2 SDK, Standard Edition v 1.2.2 support for Internet Explorer and Navigator users.

Java Plug-in is designed for enterprise customers who wish to deploy Java 2 SDK 1.2.2-based applets on their intranet web pages today. Specifically, web pages modified to support Java Plug-in enable users to run Java 2 SDK 1.2.2-based applets in Internet Explorer or Navigator. Java Plug-in integrates today's widely adopted web browsers with the benefits of all of the new features and capabilities of Java 2 SDK 1.2.2 (see http://java.sun.com/products/jdk/1.2/docs/relnotes/features.html for a list of new features found in Java 2 SDK 1.2.2).

Java Plug-in is ready for the high-performance "Project Java HotSpot" virtual machine with a future-ready architecture. This means that when Sun adds new features or functionality to the Java 2 SDK, users can take full advantage of them in Internet Explorer and Navigator immediately by deploying the latest release of the Java Plug-in. This makes the process of upgrading all users in an enterprise to the latest Java 2 SDK feature set as easy as modifying one web page on your intranet.

Java Plug-in Features

Java Plug-in delivers several key capabilities to enterprises using Internet Explorer and Navigator:

			Full Java 2 SDK 1.2.2 support: Enables enterprise developers to develop and deploy applets, taking full advantage of Java 2 SDK 1.2.2 features and functionality, such as JFC 1.1, JavaBeans enhancements and so on.
			Future-ready Java 2 SDK Architecture: Java Plug-in features an architecture that makes it easy for Sun to bring new Java 2 SDK features and functionality, including those contained in the high performance Project Java HotSpot virtual machine, to Windows and Solaris desktops much more quickly than has been previously possible.
			Free public download and easy install: Upon encountering a web page that specifies Java Plug-in, the browser will download and install all the necessary files and render the applet, requiring minimal user intervention.
			Free Java Plug-in HTML Converter: Makes it easy and automatic for IS managers and web page authors to modify their HTML pages to specify the use of Java Plug-in rather than the browser's default Java runtime.

Installing and Running the Java Plug-in

The first time the web browser encounters a web page that specifies the use of the Java Plug-in, the browser must download and install the required files. System administrators can determine where users download Java Plug-in software; either from http://java.sun.com or from an internal server. Download and install times will vary depending on the type of network connection and overall system performance. Typical total download and installation times (over a local area network) will vary from three to ten minutes. In subsequent encounters of web pages that specify the use of the Java Plug-in, it is invoked instantaneously from the user's hard drive and the applet is rendered.

Internet Explorer: When Internet Explorer first encounters a web page that specifies Java Plug-in, Internet Explorer will ask the user if it is OK to download an ActiveX control that is digitally signed by Sun Microsystems, Inc. and verifiable by the associated VeriSign Class 3 certificate. If the user says "Yes," Internet Explorer will quickly download a small ActiveX control from Sun's web site that will handle downloading the main Java Plug-in ActiveX control and Sun's JRE. This will include selecting the appropriate locale-specific JRE and offering the user a list of suitable download sites. It will then download the files automatically and install them. The Java Plug-in ActiveX control will then run and use its parameters in the <OBJECT> tag to render the applet. The next time Internet Explorer encounters a web page that specifies the Java Plug-in, Internet Explorer will seamlessly load and run the ActiveX control and JRE from the local disk, requiring no user intervention.

Netscape Navigator: When Navigator first encounters a web page that specifies Java Plug-in, users will see a plugin-missing picture on the HTML page. When the user clicks on this picture, Navigator will direct the user to the Java Plug-in download page. Users can then download the version of Java Plug-in and install it. Once it is installed, Java Plug-in will then run and use its parameters in the <EMBED> tag to render the applet. The next time Navigator encounters a web page that specifies the Java Plug-in, Navigator will seamlessly load and run the plug-in and JRE from the local disk, requiring no user intervention.

How the Java Plug-in Works

Internet Explorer: Java Plug-in leverages Internet Explorer's extension mechanisms in order to allow Sun's JRE to run inside Internet Explorer. The technology used to achieve this is Microsoft's COM/ActiveX. Using the HTML <OBJECT> tag, web page authors can run ActiveX controls or COM components as part of a web page. Internet Explorer provides elaborate mechanisms for downloading and caching ActiveX controls. This makes it possible for the web browser to use Sun's JRE with minimal user intervention.

Netscape Navigator: The Java Plug-in leverages Navigator's plug-in architecture in order to allow Sun's JRE to run inside Navigator, much like users can run QuickTime movies or Shockwave animations with plug-ins today. Using the HTML <EMBED> tag, web page authors can cause plug-ins to be run as part of a web page. This makes it possible for the web browser to use Sun's JRE in Navigator.

In order to utilize all of the features and capabilities of Java 2 SDK 1.2.2 in Internet Explorer or Navigator, web page authors must specify the use of Sun's JRE using the Java Plug-in. Thus, web pages must be modified in order to invoke Sun's JRE. Sun provides a written specification to guide web page authors on how to make these changes. In addition, Sun provides the Java Plug-in HTML Converter, free of charge, that will automatically make the changes to the selected set of HTML pages.

Java Plug-in Documentation

			Java Plug-in FAQ
			Java Plug-in Documentation

System Requirements

The minimum system requirements for the Java Plug-in on Win32 are as follows:

  - Windows 95, Windows 98 or Windows NT 4.0
  - Internet Explorer 3.02 and higher, Navigator 3.0 and higher
  - Pentium 90 MHz or faster processor
  - 25 MB free hard disk space
  - 16 MB (24 MB recommended) system RAM

Java Plug-in works best over direct LAN (that is, Ethernet) connections. It will also function properly over dial-up modem (28.8 or faster).