Java Plug-in README

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Introduction

The Java Plug-in is a software product from Sun Microsystems Inc. It enables web page authors to direct Java applets or JavaBeans components on their intranet web pages to run using Sun's Java Runtime Environment (JRE), instead of the browser's default Java runtime. This release provides support for Microsoft Internet Explorer and Netscape Navigator on various Win32 platforms and Solaris platforms (see this table for specific platform support). The Java Plug-in delivers full Java Development Kit (JDK) 1.1 support and Java Compatibility Kit (JCK) compliance to Internet Explorer and Navigator users.

The Java Plug-in is designed for enterprise customers who wish to deploy JDK 1.1-based applets on their intranet web pages today. This product ensures that enterprises realize the "write once, run anywhere" benefits of the Java platform on Win32 and Solaris systems on the most widely used web browsers. More specifically, web pages modified to support the Java Plug-in enable users to run JDK 1.1-based applets in Internet Explorer or Navigator, taking full advantage of all of the features and capabilities of JDK 1.1 (such as the JavaBeans component model, RMI, JNI, and so on), and have confidence that they will run reliably and consistently.

Java Plug-in Features

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

			Full JDK 1.1 support: Enables enterprise developers to develop and deploy applets, taking full advantage of JDK 1.1 features and functionality, such as JavaBeans, RMI, JNI, and so on.
			Full Java Compatible support: The Java Plug-in utilizes the latest release of Sun's JRE, which is fully compliant with the Java Compatibility Kit (JCK) test suite.
			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. 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 the Java Plug-in, Internet Explorer will ask the user if it is OK to download an ActiveX control signed with a VeriSign digital signature signed by Sun Microsystems, Inc. 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 the 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 for their operating system and install it. Once it is installed, the 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: The 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.

Note: There is a known conflict when using JRE 1.1.8 and the Full Circle feature in Netscape Navigator 4.6 that causes unstable behavior of Java Plug-in 1.1.3. This conflict results in the browser exiting after the user clicks "OK" in an error dialog box reporting a divide-by-zero error has occurred.

If this occurs, please disable the Full Circle software while using Java Plug-in. To disable Full Circle, do the following:

1. From the Start menu, select Programs -> Netscape Communicator 4.6 -> Utilities -> Netscape Quality Feedback Agent
2. On the Settings menu of the Feedback Agent select "Turn Agent Off"

In order to utilize all of the features and capabilities of JDK 1.1 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 uses the same JRE for Win32 and Solaris that users can download from Sun's web site today.

All JDK 1.1-based, 100% Pure Java applets should run unmodified using Java Plug-in.

System Requirements

The compressed Java Plug-in download is approximately 5 MB. After decompression and installation, Java Plug-in uses approximately 8 MB of hard disk space.

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

  - Windows 95, Windows 98 or Windows NT 4.0
  - Pentium 90 MHz or faster processor
  - 10 MB free hard disk space (recommended 20 MB)
  - 24 MB system RAM

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

  - Solaris 2.5 or 2.6
  - SPARC workstation / Pentium 90 MHz or faster processor
  - 10 MB free hard disk space (recommended 20 MB)
  - 32 MB system RAM (recommended 48 MB)

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).
 

Sun supports the following configurations: