Write AJAX applications in the Java language with Google Web Toolkit

Google Web Toolkit (GWT) is a Java software development framework that makes writing AJAX applications easy. With GWT, you can develop and debug AJAX applications in the Java language using the Java development tools of your choice. When you deploy your application to production, the GWT compiler translates your Java application to browser-compliant JavaScript and HTML.

Technorati tags: Google, GWT

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Log4j levels

Using Log4J (http://logging.apache.org/log4j/docs/), which is generally accepted as the benchmark for all Java applications. This provides the following logging levels.

  • FATAL
  • ERROR
  • WARN
  • INFO
  • DEBUG
  • TRACE – from 1.2.12, latest is 1.2.13

A description for what handling should occur per logging level.

FATAL. As the name suggests, all processing should stop. Should logging include a FATAL, the process is a Failure.

ERROR. An error has occured, and this requires attention, and action. Generally processing should stop, however additional post processing, or an alternative path could occur. Should logging include an ERROR, the process is a Failure.

WARN. Something that is unexpected occured, however it doesn’t affect the general processing from succeeding successfully. If a process includes WARN and not FATAL/ERROR it should be considered successful.

INFO. Information Only. On high volume systems, this level of logging may even be turned off. This generally indicates key information values or steps, and can assist when enabled in longer running processes to identify where a process is. You don’t log errors at INFO.

DEBUG. For Debugging Purposes only.

Ok, well that sounds like common sense. Here is what I observed on a client site.

  • Code logs a FATAL, but continues processing
  • A FATAL is logged, yet the calling process reports success
  • An ERROR is logged, yet the calling process reports success.
  • A lot of WARN are logged, and this is misleading, as it appears more information regarding XML elements not processed (We are talking 20+ Warnings per batch process). From what I’ve observed, these don’t require futher action, and should be changed in INFO.
  • Errors are being logged as INFO. A NullPointer RunTime Exception is logged as INFO. If an error provides an Exception argument where a stack trace is printed, it ain’t an INFO message.

Reference: http://blog.arabx.com.au/?cat=12

Technorati tags: Log4j

New Splash-Screen Functionality in Mustang

Splash screens are a standard part of any modern graphical user interface (GUI) application. Their primary purpose is to let the user know that the application is starting up. An application that displays a polished and professional-looking splash screen can occupy the user’s attention and gain the user’s confidence that the application is starting. In addition, splash screens may provide marketing information. And they are sometimes required for legal reasons: to present copyright information, third-party logos, and so forth.You can use Java Foundation Classes/Swing (JFC/Swing) or AWT to create splash screens in Java technology applications. However, because the main purpose of a splash screen is to provide the user with feedback about the application’s startup, the delay between the application’s startup and the moment when the splash screen pops up should be minimal. Before the splash screen can pop up, the application has to load and initialize the JVM*, AWT, usually Swing, and perhaps some application-dependent libraries. The resulting delay of several seconds has made use of a Java technology-based splash screen less than desirable. Until now.Java Platform, Standard Edition (Java SE, formerly known as J2SE) version 6, code-named Mustang, provides a solution that allows the application to show the splash screen much earlier, even before the virtual machine starts. Now, a Java application launcher is able to decode an image and display it in a simple nondecorated window.

Reference: http://java.sun.com/developer/technicalArticles/J2SE/Desktop/javase6/splashscreen/

Spring Season in IT

Introduction

Officially the spring season might be over but spring still seems to be lingering around. If you did not get the smell of the Spring Framework this summer then you might be missing something. You might be having your fingers crossed skeptically about another run of the mill Framework system that we have been seeing for the last couple of years. Hundreds of open source and propriety frameworks have sprung all over the place making it difficult to identify what each framework does, so the skepticism is understandable, but before we write off spring like one of those others it might be worth briefly peeking through it. Spring proposes a new paradigm, a pluggable, non-intrusive and robust framework.

Summary

Unlike other frameworks and APIs, spring does not impose itself wholly on to the design of a project. Spring is modular and has been divided logically into independent packages, which can function independently. The architects of an application have the flexibility to implement just a few spring packages and leave out most of the packages in spring. The “Spring Framework” would not feel bad with this attitude and on the contrary encourages users to introduce Spring into existing applications in a phased manner. So no matter what kind of framework you are using now Spring will co-exist with it without causing you
nightmares and further more Spring will allow you to choose specific packages in Spring.

The “Struts” framework is no doubt a good framework to enhance the ability of the web tier, but the biggest drawback is the fact that it caters only to the web tier and leaves most of the Enterprise tier or middle tier to the fancy of the application architects. The Application architects need to provide an additional framework to deal with the enterprise tier and make sure that the new framework integrates well with the Struts framework. Spring tries to alleviate this problem by providing a comprehensive framework, which includes an MVC framework, an AOP integration framework, a JDBC integration framework, and an EJB integration framework. It also provides integration modules for major O/R mapping tools like Hibernate and JDO. Spring provides all these in a modular fashion without imposing any layer on to the user. Spring is not a take-it-or- leave-it kind of framework. It tries to seamlessly blend into the existing framework users have without hindrances. Spring also provides transaction management support using Java classes,
email support packages using framework classes, web services support through proxies and many more features like the above. As mentioned earlier all these packages are optional and spring does not make any of them mandatory. Spring can seamlessly integrate with existing applications and provide specific functionality that you intend to provide with minimal demands for customization. A user can continue to use Struts for the web tier and toplink O/R for the database and meanwhile hook spring to provide e-mail services and web services support. Spring is based on the Inversion of Control/Dependency Injection pattern that has been making rounds in message boards all over the Internet.
Reference :
http://javaboutique.internet.com/tutorials/spring_frame/article.html