Core JSP By Damon Hougland and Aaron Tavistock - Part1

Today i strated reading Core JSP by Damon Hougland and Aaron Tavistock.

Nice book written by Damon Hougland and Aaron Tavistock.

Few important quotations i wanted to share from 1st two chapters.

1) The first web applications used the CGI (Common Gateway Interface) mechanism and a collection of server-side scripts, typically written in Perl, but occasionally in C,Python, PHP or other languages. There are numerous problems with this approach.The CGI mechanism does not scale well since every web request spawns a new server process. Communication between processes—for example, to share resources such as
database connections—is extremely awkward to program. And finally, exotic programming languages may have their charm but they lack the ability to do the "heavy lifting". Features such as database access or security are typically not part of the language but supplied by a non-standard third-party library. That puts the programmer at the mercy of not only the implementors of the language itself but also the providers of various third-party libraries.

2) Java programmers have enjoyed the power of servlets for some time, which solves many of these problems. Servlets are programmed in Java, a language that is widely supported. Java has built-in features for database access, networking, multithreading,security, and so on. Each servlet executes in its own thread, thus avoiding the cost of generating server processes. Servlets can easily share resources such as session state
and database connections.

3) JavaServer Pages (JSP) is an exciting new technology that provides powerful and efficient creation of dynamic content. JSP is a presentation layer technology that allows static Web content to be mixed with Java code. JSP allows the use of standard HTML, but adds the power and flexibility of the Java programming language.

4) JSP does not modify static data, so page layout and "look-and-feel" can continue to be designed with current methods. This allows for a clear separation between the page design and the application. JSP also enables Web applications to be broken down into separate components. This allows HTML and design to be done without much knowledge of the Java code that is generating the dynamic data. Businesses will no
longer have to hunt down the rare software developer who understands graphic design,layout, application programming, and software design.

5) Java Servlets are a powerful alternative to CGI programs and scripting languages.Servlets are extremely similar to the proprietary server APIs, but since they are written in the Java programming language they can be easily ported to any environment that supports the Servlet API. Since they run in the Java Virtual Machine,they bypass the security problems that affect the server APIs.

6) The Basics of HTTP

HTTP is a generic, lightweight protocol that is used for the delivery of HTML and XML. HTTP is the primary protocol used to deliver information across the World Wide Web.

HTTP is also a stateless protocol that keeps no association between requests. This means that when the client makes a request to a server, the server sends a response,and the transaction is closed. A second request from the same client is a whole new transaction, unrelated to the first request.

7) There are five basic types of elements, as well as a special format for comments.The first three elements—Scriptlets, Expressions, and Declarations—are collectively called scripting elements. The Scriptlet element allows Java code to be embedded directly into a JSP page. An Expression element is a Java language expression whose value is evaluated and returned as a string to the page. A Declaration element is used
to declare methods and variables that are initialized with the page.

About the Authors

DAMON HOUGLAND is a Program Manager and Technical Architect for eFORCE, Inc., where he designs and develops Java enterprise applications. Previously Damon led the Web Application Infrastructure team at Lawrence Berkeley National Laboratory, which specialized in reporting scientific data through web-enabled databases and applications. He has worked as a software developer and technical manager over the last nine years.


AARON TAVISTOCK has over 10 years of experience with UNIX systems and application development. He has used his extensive knowledge of Java, JSP, and taglibs to create a leading edge web application compiler. Aaron is currently the Web Compiler Architect for Snapshop.com, Inc., a provider of B2B2C (business-to-business-to-consumer) web applications.