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 5 and Java 6 are subsets of the Java 2 platform. Java N is interchangeable with Java 1.N. Java 1.N_r is interchangeable with Java Nur. You might install IBM's Java 6.0.0, then issue a "what version" command and see 1.6.0. You might download Java 1.6.0_14 from Oracle and get a file named 6u14 |
| 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. |
| Oracle / Sun: | Java used to belong to Sun Microsystems. It now belongs to Oracle Corporation. |
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 packaged in *.jar archives.
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 Oracle's Java Runtime Environment (JRE)
SDS recommends using the newest version of the JRE.
The download comes from Oracle Corp. It is free of charge and simple to install, provided you have administrative rights to the client machine. At the download site, look for a link to a JRE (not a JDK).
The download gets you an executable file (jre-6u24-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:
| • VFTP 3.0: | JRE 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VFTP 2.0: | JRE 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.3: | JRE 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.2: | JRE 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.1: | JRE 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VNAC 2.0: | JRE 6u10 (1.6.0_10+) |
| • VNAC 1.1: | JRE 6u10 (1.6.0_10+) |
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) |
| • IE 9 | JRE 6u25 (1.6.0_25) |
| • IE 8 | JRE 6u13 (1.6.0_13) |
| • Firefox 5 | JRE 6u27 (1.6.0_27) |
| • Firefox 4 | JRE 6u25 (1.6.0_25) |
| • Firefox 3.6 | JRE 6u10 (1.6.0_10), says Mozilla; or 6u18 (1.6.0_18), says Oracle |
For details, see Oracle's release notes for Java 6 Java 5
To download something other than the latest version of Java tools, see Oracle'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 July 2011, IBM lists four versions, in 31-bit and 64-bit forms.
IBM's support for version 1.4.2 ends 30 September 2011.
In all cases, SDS recommends using the latest refresh level of a given version.
We do not test with any level older than 2 years.
VitalSigns Servers on z/OS USS work in the following Java environments:
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• For IBM z/Linux: see Linux Download information
• For Linux, Solaris Unix, Windows: get Oracle's Java Development Kit (JDK)
SDS recommends using the newest version of the JDK.
The download comes from Oracle Corp. 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).
Oracle'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.
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:
| • VFTP 3.0: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VFTP 2.0: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.3: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.2: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VIP 7.1: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VNAC 2.0: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
| • VNAC 1.1: | JDK 6u10 or 5u9 (1.6.0_10+, 1.5.0_09+) |
To download something other than the latest version of Java tools, see Oracle's product archive.
The "Next-Generation" Java Plug-in
VNAC wants the next-generation plug-in enabled.
The JRE/Java plug-in version 6.0 update 10 (1.6.0_10) introduced the "next-generation Java Plug-in."
The next-generation feature is enabled by default.
For VitalSigns for Network Automation and Control (VNAC), SDS recommends that browser-clients have the next-generation plug-in enabled.
However, the next-generation plug-in sometimes fails to properly support applets designed for the previous generation.
If you have administrative rights to your machine, you can enable or 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.
Enable or disable the next-generation plug-in as follows:
- 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 next to the label Enable the next-generation Java Plug-in.
A check mark means the next-generation is enabled (and VNAC is happy).
An empty box means it is disabled. - 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.