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HashCode and equals methods
Author :
Christy
Date : Tue Aug 21st, 2007
HashTable, HashMap and HashSet are the Collection classes in java.util package that make use of hashing algorithm to store objects. In all these Collection classes except HashSet, objects are stored as key-value pairs. For the storage and the retrieval of any user-defined objects it is a good practice to override the following methods which is mentioned below,
Using the new Process Builder class
Author :
Christy
Date : Tue Aug 21st, 2007
We all know how to execute programs from within a Java Application by making use of the Runtime Api. For example, assume that we want to launch the Internet Explorer browser within the Java code. Then the following code snippet will just do that,
Singleton Pattern - Design Patterns in Java/J2EE
Author :
Christy
Date : Tue Aug 21st, 2007
Situations often will demand for the existence of only one object for a particular class in an Application. For example, the existence of only one Database Connection for a particular session, one object referencing the set of Global properties being shared across the various modules, etc.
Template method Pattern - Design Patterns in Java/J2EE
Author :
Christy
Date : Tue Aug 21st, 2007
A Template method pattern provides a skeleton for performing any sort of algorithm or an operation, and it allows the sub-classes to re-define part of the logic. Let us directly get into an example to clarify things in a much better manner. For example, if we wish to write a String Decorator class,
State Pattern - Design Patterns in Java/J2EE
Author :
Christy
Date : Tue Aug 21st, 2007
State pattern falls under the category of Behavioural patterns. Assume that we have an object and its behavior is largely dependent on the state of its internal variables. Consider the following example,
Expression Language in JSP 2.0
Author :
Nissi
Date : Mon Aug 20th, 2007
Expression Language was first introduced in JSTL 1.0 (JSP Standard Tag Library ). Before the introduction of JSTL, scriptlets were used to manipulate application data.JSTL introduced the concept of an expression language (EL) which simplified the page development by providing standerd tag libraries. These tag libraries provide support for common, structural tasks, such as: iteration and conditionals, processing XML documents, internationalization and database access using the Structured Query Language (SQL).
The Expression Language introduced in JSTL 1.0 is now incorporated in JavaServer Pages specification(JSP 2.0). This articie gives some idea about what is Expression Language and how to simplify the maintenance for JSP applications by avoiding scripting elements.
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