My Java Experience

2009-08-26T14:41:00.009+05:30

Google App Engine

Build a Java / Python based killer application in Google's environment.

Google App Engine lets you to build application and run it on Google's scalable infrastructure.
Google App Engine supports apps written in Java or Python. In the case of App Engine's Java runtime environment, you can build your app using standard Java technologies, including the JVM, Java servlets, JDO, JPA, Java Mail, JCache etc.
Google App Engine also features a dedicated Python runtime environment, which includes a fast Python interpreter and the Python standard library.

About Google App Engine:

First they released in April 2008, but it is purly for Python programmers. Finally they released it for Java lovers after an year, April 2009. Google App Engine for Java provides an end-to-end solution for enterprise Java development: a browser-based Ajax GUI for ease of use, Eclipse tool support, and Google App Engine on the back end. Ease of use and tooling are advantages of Google App Engine for Java over other cloud computing solutions.

BigTable is used for data storing in Google App Engine(GAE). But with JDO and JPA interfaces that allow you to write code that is not directly tied to BigTable.

Also GAE provides the application services like Authentication and Authorization, CRON, Importing and Exporting of data and Access to Firewall data.

Easy to build, Easy to maintain, and Easy to scale

Google App Engine provides Google’s environment for building and deploying our application. So App Engine applications are easy to build, easy to maintain, and easy to scale as your traffic and data storage needs grow. That means , just create an application and upload and it is ready to serve your users.

You can make it as your own domain name or use Google’s free domain names on appspot.com. Also you can set the privileges in the case of visitors. All applications can use up to 500 MB of storage and enough CPU and bandwidth to support an efficient app serving around 5 million page views a month, absolutely free. What else you want?

I just created a sample app engine application and hosted it in app engine server. http://demotrackingsystem.appspot.com/addtask.jsp

2009-05-03T09:50:00.004+05:30

DHTMLx - Easy way for client-server communication

Quick creation of graphic interface structure of an application in order to concentrate developers' efforts on business logic creation. This component provides extensive server side API’s and support different database engines.

DHTMLx provides lots of controls some of them are :

1. dhtmlxTree : is a feature rich JavaScript tree menu that allows you to effortlessly create attractive and fast-loading hierarchical interfaces with cross-browser compatibility, AJAX support, in-line node editing, and drag-n-drop capabilities. Rich client-side API provides complete control over the tree appearance and behaviour.

2. dhtmlxGrid : This is an Ajax-enabled JavaScript grid control with cutting-edge functionality, powerful data binding, and excellent performance with large datasets. The gridview component is easy-to-use and provides great flexibility due to its rich client-side API. dhtmlxGrid supports different datasources, including XML, JSON, CSV, JS array, and HTML table. Since v1.6 grid data can be loaded from custom XML format.

3. dhtmlxMenu : It is an Ajax-enabled JavaScript menu that represents an excellent solution for web navigation. This completely customizable and slick menu component allows you to integrate an attractive DHTML navigation menu effortlessly into your web site or application.

4. dhtmlxToolbar : This is a cross-browser JavaScript component enables you to create an attractive horizontal DHTML toolbar within minutes. dhtmlxToolbar is flexible, powerful, lightweight and easy to use.

5. dhtmlxLayout : dhtmlxLayout is a JavaScript DHTML component that provides powerful and efficient solution for building Ajax-enabled web interfaces with ease. This component allows you to programmatically define interface structure, including layout of elements and their sizes. End users can easily resize interface elements, collapse or expand them.

You can download these components from the dhtmlx website for development purpose. Click here

Google Chrome Tips

2008-10-02T23:20:00.005+05:30

As we all know about Google’s new web browser "Chrome". Here are some tips that you can do in Google Chrome.

1. Undo closing a tab: press Ctrl+Shift+T or open a new tab and check the "Recently closed tabs" section.

2. Focus on the default search option in the address bar: type ? before entering your query.

3. Show the list of recently visited pages from the current tab: right-click on the "Back" button. This also works for the "Forward" button.

4. Perform simple calculations and unit conversions using Google Calculator by simply typing the expression in Google Chrome's address bar (or "omnibox"). To copy the answer, select the suggestion.

5. If you need more space in a textarea, resize it by dragging the lower right corner.

6. Detach a tab and open it in a new window - just drag the tab outside the active window. You can also add it back to the original window using drag and drop.

7. Download : After downloading a file, you can copy it to the desktop or to any other folder by using drag and drop directly from Google Chrome.

8. There are lots of secret about pages in Google Chrome which you access by typing their URL in address bar and press Enter. All known About pages are as following:

about:memory
about:stats
about:network
about:internets
about:histograms
about:histograms/Loop
about:dns
about:cache
about:plugins
about:version
about:crash
about:%
about:ipc
about:shorthang
about:hang
about:objects
about:chrome-nativeui
view-cache:[Full_URL_of_Website]
view-source:[Full_URL_of_Website]

You can download Google Chrome using this link : http://www.google.com/chrome

Download Portable Version of Google Chrome, No Need to Install

If you don’t want to install Google’s new web browser “Chrome” in your system but still want to try it, then here is a good news for you.

A portable version of Google Chrome is available. Just download it and unzip it. Now you can run it and use it without any problem. No need to install. You can even carry it on your USB drive anywhere you want.

Click here

Web 2.0

2008-07-12T13:09:00.004+05:30

Is it another version of Internet ?? No.. It is not.. The term web 2.0 has got nothing to do with a product version or some enhancements to the current internet. It signifies the change in approach to creating websites. In the case of Technology wise there is something different in Web 1.0 and Web 2.0.

In the case of Web 2.0 it provides a better User Experience . That means it focused on Participation, Collaboration and Networking. The users can achieve something collaboratively. The users can network with other users and also participate in an activity. ie Web 2.0 is both Read and Write enabled web., but Web 1.0 is read only web.

Consider the example of Blogs. You can create your own space in internet and write any thing that you want. Also you can upload files, pictures etc.. And also the readers interact with you through with comments. But in the case of Web 1.0 there is no way that a user can create a such things like this. Another good example is Wikipedia, worlds largest collaborative project and some google products like google map, Youtube etc. Wikipedia provides you a Wiki page and allows you to create something collaboratively.

Are you still in old web 1.0 ?? Come on .. Start a blog or participate a social network form.. and be a part of Web 2.0..

2008-06-26T22:59:00.004+05:30

TestNG - Next Generation Java Testing

TestNG, written by Cedric Beust and Alexandru Popescu, is a light framework based on Java annotations (for J2SE 5.0) that allows you to design complex unit testing for J2SE 5.0 and J2SE 1.4. If you are interested in simplifying your unit-test cases, in leveraging J2SE 5.0 annotations to tag your test classes as well as being backward compatible with J2SE 1.4, in having out-of-the-box support for dependent methods and parallel and asynchronous testing, TestNG is the tool you are looking for.

In JUnit Multiple TestCase instantiations is a well-known issue. The setup() and teardown() methods are called before and after each test method; Although multiple TestCase instantiations might prove acceptable for simple test cases, what if you want to set up an object that is to be reused across more than one test method, for example, a Java Database Connectivity connection ? In this case, this is the one of the main advantage of TestNG. That is TestNG does not require static block initialization and has a flexible configuration scheme for handling test classes based on regular expressions and XML configuration files. TestNG does not instantiate the test class several times.

Also TestNG handle multithreaded unit testes. TestNG has multithreaded and parallel unit tests built in its core. You don't need to write specific code to handle multithreaded unit tests as they are just a configuration of TestNG.

TestNG is a testing framework inspired from JUnit and NUnit but introducing some new functionalities that make it more powerful and easier to use, such as:

- JDK 5 Annotations (JDK 1.4 is also supported with JavaDoc annotations).
- Flexible test configuration.
- Support for data-driven testing (with @DataProvider).
- Support for parameters.
- Allows distribution of tests on slave machines.
- Powerful execution model (no more TestSuite).
- Supported by a variety of tools and plug-ins (Eclipse, IDEA, Maven, etc...).
- Embeds BeanShell for further flexibility.
- Default JDK functions for runtime and logging (no dependencies).
- Dependent methods for application server testing.

Download : http://testng.org/doc/download.html

2008-05-28T00:06:00.003+05:30

Three forms of AJAX: Solid, Liquid and Gas.

Looks like today AJAX concept have several different interpretations. According to the way applications use XMLHttpRequest, we can distinguish three main strategies of AJAX integration:

- Application-specific JavaScript that play a role of presentation controller on the client-side.
- Component oriented form
- Sub-page oriented form.

The first form refers to pure JavaScript developments. Solutions, implementing this form are the most flexible and powerful. They allow creating amazingly rich user interfaces. However, because of well-known limitations of JavaScript, they are quite hard to develop, debug and maintain. In addition, if multi browser support is required, you will probably have to develop a second AJAX-free version of your UI.

Component oriented form is both flexible and easy to maintain. Components do not necessarily expose JavaScript to developers, thus making their job easier. Auto-complete or auto-validating text fields, AJAX-aware trees and updatable data grids are typical examples of this approach. Its main disadvantage is the scope that rarely exceeds a single component (or set of similar components).

The third form is sub-page oriented form of AJAX integration. It refreshes "zones" on the page. While being less powerful then other forms, it is ideally suited for upgrading existing projects. It does not have visible scope limitations and preserves the original MVC architecture (presentation controller stays on the server side). Another advantage of this form is graceful degradation possibilities. The same presentation code can support both AJAX and traditional modes.

Unfortunately, all those forms seem to be mixed up under the same buzzword and compete with each other in developers’ minds.
[source : theserverside.com ]

2008-05-20T21:42:00.003+05:30

DISPLAY TAG - reduces pain of JSP development

JSP development can be a bit "cumbersome". A diffuse set of often fairly limited tag libraries abound. It's therefore surprising that the open source display: tag library has gotten so little attention. This gem is a mature render kit for all sorts of lists, ideal for overview-detail screens. It supports sorting, grouping, alternate row colors, export functions and decorators to fulfill most if not all of your display needs. And, it looks cool.
Also you can Export to Excel,CSV, and XML, sorting, and paging are available as simple configuration options. The look and feel can be controlled by adding custom styles. The libraries are well documented and very stable in my opinion. While I do agree that reading the entire list into memory may be unacceptable for some applications, this library works great when you are dealing with small to medium result sets

Visit this site for more information and download
http://displaytag.sourceforge.net/

RichFaces

2008-04-18T22:45:00.002+05:30

Rich Faces is an open source framework that adds Ajax capability into existing JSF applications without resorting to JavaScript. Rich Faces leverages JavaServer Faces framework including lifecycle, validation, conversion facilities and management of static and dynamic resources. Rich Faces components with built-in Ajax support and a highly customizable look-and-feel can be easily incorporated into JSF applications.

RichFaces was originally developed and open-sourced at JBoss by Exadel [http://exadel.com/]

RichFaces enriches the Ajax4jsf framework in two important ways. First, it expands a number of visual ready-to-use components. Secondly, it fully implements the skinnability feature of the Ajax4jsf framework including a large number of predefined skins. Using skinnability, it is much easier to manage the look-and-feel of an application.

RichFaces Live Demo [http://livedemo.exadel.com/richfaces-demo/index.jsp]

JBoss RichFaces Downloads

[http://www.jboss.org/jbossrichfaces/]

JBoss Seam

2008-03-28T15:38:00.000+05:30

JBoss Seam is a powerful new application framework for building next generation Web 2.0 applications by unifying and integrating technologies such as Asynchronous JavaScript and XML (AJAX), Java Server Faces (JSF), Enterprise Java Beans (EJB3), Java Portlets and Business Process Management (BPM).

The core frameworks in Java EE 5.0 are EJB (Enterprise JavaBeans) 3.0 and JSF (JavaServer Faces) 1.2. EJB 3.0 (EJB3, hereafter) is a lightweight framework based on Plain Old Java Ob- jects (POJO) for business services and database persistence. JSF is a Model-View-Controller (MVC) component framework for web applications. Most Java EE 5.0 web applications have both EJB3 modules for business logic and JSF modules for the web front end. However, although EJB3 and JSF are complementary to each other, they are designed as separate frameworks, each with its own philosophy. For instance, EJB3 uses annotations to configure services, whereas JSF makes use of XML files. Furthermore, EJB3 and JSF componenvs are not aware"of gach"othgr av thg frcmework neven. To make EJB3 cnd JSF work"toggther.