Installation Instructions for Java Runtime Environment and Java Servlet Engine for All Platforms

What exactly is Java Runtime Environment (JRE)?

JRE is an underlying environment for Java applications to run. JRE provides a layer that makes Java platform neutral language.

Java Development Kit (JDK) is the development environment used by developers to create Java applications. JRE comes as a part of JDK, and also as standalone component. Where development environment is not required, administrators can consider installing on JRE. Installing JDK is preferable.

Ad Server Solution has been developed using version 1.5 of JDK/JRE. To be able to run this application successfully, 1.5 or higher version must be installed.

To install JDK/JRE, visit http://java.sun.com. Detailed installation instructions are also available with software.

If JDK/JRE are used to run Java applications, what is Java Servlet Engine (JSE) needed for?

JSE or web container is a set of APIs that are needed to run Java servlets and Java Server Pages. These are building blocks for developing web applications.

There are several free and commercially available JSE. This FAQ provides details about three freely available JSE that can be implemented by system administrators.

How do I choose a JSE?

Choice of JSE can depend on factors like prior experience of administrators, ease of implementation and of course platform. All JSEs, however, have versions suitable for most platforms.

A list of all major JSE, both free and commercial, used in the industry can be found at http://java.sun.com/products/servlet/industry.html.

Ad Server Solution recommends Tomcat from Apache Foundation. Tomcat has been endorsed by Sun and is most widely used JSE for all types of platforms. Download Tomcat from the following links: 

http://java.sun.com/products/servlet/download.html
http://jakarta.apache.org/tomcat/index.html

I have decided on a JSE? What do I do next?

Your system administration task begins here. Following paragraph provides information on overall concepts of installation. This will enable you you to jump straight into installation instructions provided with your product download.

Types of Web Containers 

There are mainly three types of web containers in the market. They are: 

1. Web container in a J2EE application server - most of the commercial J2EE application server such as BEA's WebLogic, Borland's Inprise Application Server, Netscape's iPlanet Application Server, IBM's WebSphere Application server, etc. now include web containers built in. 

2. Web containers built into web servers - here the web container is integrated with web server. They are Sun's Java WebServer and Jakarta Tomcat from Apache project. Both includes a web server along with a web container. 

3. Web container in a separate runtime - In this case, web server communicates with web container, which is outside the address space of the web server. The examples include Apache and Microsoft IIS, which require a separate Java runtime to actually run servlets and web server plug-in to integrate the Java runtime with the web server. The plug-in handles communication between the web server and the web container. Commercially available servlet/JSP engines such as Allaire's JRun provide plug-in to integrate with web servers. Thus through plug-ins various web servers can configured to work with containers, which are in separate runtime.

Where do I start with web container installation? What other specifics do I need to look into?

Any web container you choose will be accompanied by detailed installation instructions. However, some things to take note of before you begin installation are:

1. Chances are that you will already be using webserver like Apache or IIS. Many web containers are also web servers, but we recommend that you continue to use your existing web server.
2. Connector software will be available for you to connect your existing web server with web container for both Apache and IIS. Install the connector software and set it up so that all JSP/Servlet requests from browsers are forwarded by webserver to web container for processing.
3. While advert directory for ad servers software can reside in web container directory structure, it is advisable to create a separate advert directory under your domain root (e.g. http://www.yourdomain.com/advert). You must then change server.xml file in web container configuration to reflect the application directory path. 

For detailed instructions on Tomcat installation, please visit http://jakarta.apache.org/tomcat/tomcat-5.5.9-doc/uguide/tomcat_ug.html. Also, internet has many useful sites that will provide a wealth of information on intricacies of tomcat-apache installation. Given below are some links you may visit:

Click here for examples of various files that will change in tomcat-apache environment. For other web containers, you may follow similar strategy and may contact ad server solutions for help.

Once I install a JSE, how do I know everything has gone well? What next?

Every installation instruction provides examples. If you are able to run these examples, it will indicate that installation has gone well. From administrator perspective, you might consider modifying your start up scripts so that JSE comes up every time you reboot your systems.

You will need to ensure that what ever request your customer has made is met. E.g. a directory called /advert must be available which is accessible from the web and JSP pages should be served. Take setup.jsp from adserver solution software package or any other JSP file. Access http://www.yourdomain.com/advert/setup.jsp and make sure you see an HTML page. If your web container is not set correctly, you might see the exact .JSP file appearing as text on your browser.

Do I have to set any environment variables?

No, there is no need to set any environment variable in the version 4.0. This requirement is removed from the system. Now the version 4.0 is independent of any environment variable.   

Any special instructions if I decide to go ahead with Tomcat?

Tomcat is both a JSE and a webserver. However, its webserver capabilities are not as good as its JSE capability.  This factor usually drives administrators towards continued use of existing web servers like Apache and IIS and use Tomcat as web container running outside the address space of webserver. Connecters are available so that webserver can forward all JSP/Servlet requests to Tomcat, whenever they encounter such requests.

Ad Server Solutions 1996-2007. Any reproduction or editing by any means mechanical or electronic without the express written permission of the copyright holder is strictly prohibited.