Book Image

Java EE 7 First Look

By : Armel Fabrice NDJOBO
Book Image

Java EE 7 First Look

By: Armel Fabrice NDJOBO

Overview of this book

For several years, the development of robust, scalable, and secured applications was a headache for software companies. They had to use proprietary solutions with non-standard methods. With Java EE, many of these solutions have been standardized, simplified, adapted to the needs of the developer, and made freely available to the community. Thus, it is now possible to develop truly robust, secure, and scalable applications at a lower cost using tools such as: Eclipse, NetBeans, and GlassFish.Java EE 7 First Look is a practical guide which, through the creation of an online pre-registration website, will introduce you to the novelties of Java EE 7 and give you ideas for utilizing them.Giving you an insight on new features introduced in Java EE 7, this book begins with the objectives of Java EE 7 and then covers the new specifications added in Java EE 7. Next, you will move on to the improvements made in APIs and EJBs and how to work with them. You will also learn how to ensure that the quality of data is maintained that has been manipulated by your application and gives you the opportunity to put a small part of AOP (Aspect Oriented Programming) in action.Finally, the book will give you some ideas to realize n-tier applications using the Java EE platform and will also provide some guidance for the integration of your Java EE application to heterogeneous systems with which your application will interact.After reading Java EE 7 First Look, you'll have a good idea about the changes brought in by Java EE 7, as well as how to make the best use of these to build a large-scale application.
Table of Contents (16 chapters)

Expression Language 3.0

The Expression Language 3.0 Specification was developed under JSR 341. This section gives you only an overview of improvement in the API. The complete document specification (for more information) can be downloaded from

What is Expression Language?

Expression Language (EL) is a language used to access and manipulate data in your JSP or JSF web pages. It provides a simple way to:

  • Read/write data from/to JavaBean component properties

  • Invoke static and public methods

  • Perform arithmetic, relational, logical, and conditional operations

An EL expression looks like ${expr} or #{expr}. The former syntax is often used for immediate evaluation while the latter is used for deferred evaluation. The following code demonstrates how to access a JSF bean property from a JSF page and how to perform an operation between two integers using EL expressions: