About Java
Java support for browsers and servers: How to install it and how it works.
| Contents: | Glossary, Java Plug-In for Browsers/Clients, Java SDK for Servers, |
| The "Next-Generation" Java Plug-In, Introduction to Java |
Glossary:
| Browser/Client: | Web browsers are also known as clients. The two most common are Internet Explorer and Firefox. |
| Java plug-in: | Browsers/clients use a Java plug-in to run Java applets. The plug-in is also known as the JRE, Java Runtime Environment, or Java Runtime Engine. |
| Java applet: | Small Java programs linked into web pages. A web page loads in the browser, then an applet runs on the client machine and the browser displays the output. |
| Java SDK: | Web servers use a Java SDK to run Java programs at the server. The SDK, or software development kit is also known as the JDK or J2SDK. |
| Java versions: | Java version numbers come in multiple forms: Java 5uN or 1.5.0_n is Java 5 update N, a subset of Java 5. Java 6uN or 1.6.0_n is Java 6 update N, a subset of Java 6. Java 5 and Java 6 are subsets of the Java 2 platform. |
| J2SE: | J2SE and Java SE refer to the Standard Edition, which is adequate for SDS VitalSigns products. J2EE means Enterprise Edition, a larger package than necessary for SDS products. |
Java Plug-In for Browsers/Clients
You are using:
operating system unknown,
browser unrecognized,
JRE version unknown
If you can see the red and green circles above, your browser supports applets.
For browsers/clients, get Sun's Java Runtime Environment (JRE)
SDS recommends using the newest version of the JRE. In February 2010, that is Java 6 update 18 (1.6.0_18).
The download comes from Sun Microsystems. It is free of charge and simple to install, provided you have administrative rights to the client machine. Look for a link to a JRE (not a JDK).
The download gets you an executable file (jre-6u10-windows-i586-p-s.exe for example). Copy that file to the client machine and run it. It will install the JRE, typically at C:\Program Files\Java\.
In Windows, the JRE controls are at Start/ Settings/ Control Panel/ Java.
If your browser has trouble with applets, the most likely fix is to install or re-install the JRE and/or get the new version of it.
Earlier JRE versions:
In many cases, earlier JRE's will work for SDS VitalSigns clients.
We suggest the following as minimum VitalSigns requirements:
| • VNAC 1.1: | JRE 6u10 (1.6.0_10+) |
| • VIP 7.1: | JRE 6u10 (1.6.0_10+), 5u9 (1.5.0_09+), or 1.4.2_13+ |
| • VFTP 2.0: | JRE 6u10 (1.6.0_10+), 5u9 (1.5.0_09+), or 1.4.2_13+ |
On the other hand, newer operating systems and browsers often pose constraints that exceed VitalSigns' requirements. Most notably:
| • Windows 7 | JRE 6u16 (1.6.0_16) |
| • Windows Vista | JRE 6u16 (1.6.0_16) or 5u14 (1.5.0_14) |
| • Firefox 3.6 | JRE 6u10 (1.6.0_10), says Mozilla; or 6u18 (1.6.0_18), says Sun |
For details, see Sun's release notes for Java 6, Java 5, and Java 1.4.2
To download something other than the latest version of Java tools, see Sun's product archive.
Java SDK for Servers
VitalSigns product servers from SDS, like many "Web Application Servers," require that their hosts provide a Java SDK.
An SDK is free of charge, simple to install, and provides two components essential to Java application servers: a JRE and a Java compiler.
• For IBM USS on z/OS: get IBM's Java 2 Technology Edition
In February 2010, IBM lists three versions, in 31-bit and 64-bit forms.
VitalSigns servers work in the following environments:
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*To run the SDK 1.4.2 on z/OS 1.6 or older, consult the IBM web site regarding the prerequisite maintenance.
• For IBM z/Linux: see Linux Download information
• For Linux, Solaris Unix, Windows: get Sun's Java Development Kit (JDK)
SDS recommends using the newest version of the JDK. In February 2010, that is Java 6 update 18 (1.6.0_18).
The download comes from Sun Microsystems. It is free of charge and simple to install, provided you have administrative rights to the server machine. Look for a link to a JDK (not a JRE).
If your IE browser can't download *.bin files, try a Firefox browser.
Earlier JDK versions:
In many cases, VitalSigns Servers will work with earlier JDK versions.
We suggest the following as minimum VitalSigns requirements:
| • VNAC 1.1: | JDK 6u10 (1.6.0_10+), or 5u9 (1.5.0_09+) |
| • VIP 7.1: | JDK 6u10 (1.6.0_10+), 5u9 (1.5.0_09+), or 1.4.2_13+ |
| • VFTP 2.0: | JDK 6u10 (1.6.0_10+), 5u9 (1.5.0_09+), or 1.4.2_13+ |
Sun's download will get you an executable file (jdk-6u10-windows-i586-p.exe for example). Copy that file to the Server's host machine and run it. It will install the JDK.
To download something other than the latest version of Java tools, see Sun's product archive.
The "Next-Generation" Java Plug-in
With JRE/Java plug-in version 6.0 update 10 (1.6.0_10), Sun introduced the "next-generation Java Plug-in."
The next-generation feature is enabled by default, but it often fails to properly support applets designed for the previous generation.
If you have administrative rights to your machine, disable the next-generation plug-in as described below.
If you do not have administrative rights to your machine, attempting to disable the next-generation plug-in will fail. You may or may not see an error message, and the text of that message may be quite misleading.
Any update of the JRE, including an automatic update, will likely re-enable the next-generation plug-in.
- Open the Java Control Panel.
In task bars and program lists, look for the coffee cup icon and double-click on it.
- In the control panel, select Advanced, then Java Plug-in.
- Click on the box to uncheck the option Enable the next-generation Java Plug-in.
- In the lower-right, click on the Apply button.
- Now close and re-open the control panel and check whether your change persists. If the box returns to the checked state, the next-generation plug-in is still enabled; you do not have adequate rights to disable it.
- Re-start your web browser.
Introduction to Java
The Java 2 Standard Edition (J2SE) platform is simple to install and available free-of-charge for Windows, Linux, and Solaris.
Java Servlets and Beans are compiled binary code on a web server. When a browser-client requests a servlet or bean, the server and its host run the Java program, the program returns HTML code to the server, then the server sends the HTML to the browser-client.
Java Server Pages (JSP, file-name *.jsp) are text files on a web-server. They contain a combination of HTML code and Java source code. When a browser-client requests a JSP, the server and its host first compile, then run the Java code, the Java returns HTML code to the server, then the server sends the HTML to the browser-client. After the first request, the compiled Java code is cached on the server for quick access next time.
Java Applets are binary files on a web server. When a browser-client requests an HTML page that includes a link to an applet, the server sends the applet down to the browser. The Java code then runs on the browser's host machine and its output appears in the browser window.
Running Java programs requires a Java Runtime Environment (JRE or J2RE).
Compiling Java source code requires a Java compiler.
The JRE and compiler are parts of the Java 2 Software Development Kit (J2SDK).
The JRE can also be downloaded and installed separately, as a browser plug-in.