Direct Web Remoting (DWR), is an open source Java library that can be used to implement Ajax in Java web applications with minimal Javascript coding. Using DWR, we can invoke server-side Java methods from Javascript in the browser. DWR 2.0 introduces a new feature, dubbed "Reverse Ajax", using which server-side Java can "push" updates to the browser. In this post, I tried to use a simplistic web application that will demonstrate the use of DWR for "Reverse Ajax".... more »

JSON (JavaScript Object Notation) is a lightweight data-interchange format based on a subset of the JavaScript Programming Language. JSON object structure is built on two structures:... more »

Hibernate EntityManager implements the programming interfaces and lifecycle rules as defined by the EJB3 persistence specification. Together with Hibernate Annotations, this wrapper implements a complete (and standalone) EJB3 persistence solution on top of the mature Hibernate core. In this post I will describe how map native queries (plain SQL) using Hibernate Annotations. Hibernate Annotations supports the use of Native queries through the @NamedNativeQuery and the @SqlResultSetMapping annotations.... more »

Acegi Security uses the SecurityContextHolder object to store details of the current security context of the application. The SecurityContext holds the details of the authenticated principal in an Authentication object. By default the SecurityContextHolder uses a ThreadLocal to store these details, so that they will be available all methods in the current thread of execution.In order to obtain the Principal, you would use the following line... more »

While the next version of WAS (v7.0) with Java EE 5, is yet to be released, you can now test some of the features such as EJB 3.0 with WebSphere software early programs. The new features are available as feature packs for the current WebSphere Application Server (v6.1).... more »

The Java EE 5 Security services are provided by the container and can be implemented using declarative or programmatic techniques. In addition to declarative and programmatic ways to implement security (in J2EE), Java EE 5 supports the use of metadata annotations for security. This post will describe how to secure EJB 3.0 beans. The post consists of a simple EJB, with a web client. In order to run the example, follow these steps.... more »

This is an extension of a previous post that described how to secure your method calls using Acegi security. Here, I will go through how to secure your Asynchronous calls, using the same example with some modifications to include Ajax calls using Direct Web Remoting (DWR).... more »

BlazeDS is a server-based Java remoting and web messaging technology that enables communication between back-end Java applications and Adobe Flex applications running in the browser. In this post, I describe a way (may not be the best) I was able to successfully to build a simple application using BlazeDS and Flex. The application is build using eclipse and ant, rather than using FlexBuilder. Following are the main steps that you have to follow to implement the example.... more »

I am currently evaluating some web frameworks for a pet project and was trying to implement Struts 2 with tiles. Neither the Sturts 2 website, nor the tiles website gave an easy way to integrated Struts 2 and tiles. It took me a while to get them to work together. This post describes a way I figured out how to integrate Struts 2 with tiles. Struts 2 provides a plugin for integrating tiles 2. This plugin is included in the complete bundle (struts-2.x.x.x-all.zip). The following are are the steps needed to integrate struts2 with tiles.... more »

In a previous post, I described how to use validations in Struts 2, using XML validation rules. This post will show how to use Annotation based validation in Struts 2. For this example I used the add transaction part of google's portfolio manager (noticed that they do not have validations over there). Struts 2 provides a number of validators for XML based validation rules. All of them have respective annotations defined and can be used in place of XML validation rules. In the example, we will use the @RequiredStringValidator, @RegexFieldValidator and also see how to parameterize messages when using annotations.... more »