The Singleton Pattern Ensure a class only has one instance, and provide a global point of access to it.For example ,if we need a connection to single database at one time  or when ever we are referring to to single application.properties file in struts application for showing application in one language at one time.Then we [...]

1) What is servlet? Ans: Servlets are modules that extend request/response-oriented  servers, such as java-enabled web servers. For example, a servlet might be responsible for taking data in an HTML order-entry form and applying the business logic used to update a company’s order database. 2) What are the classes and  interfaces for servlets? Ans: There [...]

What is JSON? JSON (Javascript Object Notation) is a light weight data interchange format. JSON is a subset of the literal object notation in JavaScript. It can be compared to XML but parsing of JSON is very much easier than XML data. It is a text format of data and is programming language independent. In [...]

Adapter Design pattern – Structural Patterns Adapter pattern Convert the existing interfaces to a new interface to achieve compatibility and re usability of the unrelated classes in one application. Also known as Wrapper pattern. An adapter allows classes to work together that normally could not because of incompatible interfaces, by providing its interface to clients [...]

A map is an interface in the java.util package which stores the association between key and its corresponding value. A map cannot contain duplicate keys; each key can map to at most one value Map differs from array in a way that we can store a value at a particular index in arrays but a [...]

Quartz is a full-featured, open source job scheduling service that can be integrated with, or used along side virtually any Java EE or Java SE application – from the smallest stand-alone application to the largest e-commerce system. Quartz can be used to create simple or complex schedules for executing tens, hundreds, or even tens-of-thousands of [...]

The Model View ViewModel (MVVM) is an architectural pattern used in software engineering that originated from Microsoft as a specialization of the Presentation Model design pattern introduced by Martin Fowler. Largely based on the Model-view-controller pattern (MVC), MVVM is targeted at modern UI development platforms (Windows Presentation Foundation and Silverlight) in which there is a [...]

We already have been visualizing the earth on our desktops for quite a long time now. Thanks Google Earth and Bind maps. Ever wondered if we could visualize space this way as well? Imagine taking a close look at a stars or galaxies like Milky way right from your desktop? Or even taking a view [...]

Castor is an open source data binding framework for moving data from XML to Java programming language objects and from Java to databases. It’s the shortest path between Java objects, XML documents and relational tables. Castor provides Java-to-XML binding, Java-to-SQL persistence, and more. Castor is made up of (independent) modules as follows:- Castor XML – [...]

The Reflection API allows Java code to examine classes and objects at run time. The new reflection classes allow you to call another class’s methods dynamically at run time. With the reflection classes, you can also examine an instance’s fields and change the fields’ contents. Reflection is commonly used by programs which require the ability [...]