By necessity, the operating system loads each VM into its own separate process slot. Consequently, each VM is forced to duplicate the other's initialization efforts and resource allocations. Specifically, each VM is required to load the JDK core classes into their respective heap spaces. Running several Java applications in the same VM would eliminate this duplication of effort. There's an analogy in the world of operating systems...

Introduites avec Java 1.1, les classes internes et anonymes facilitent la compréhension et la maintenance du code. Explications.
Java 1.1 (lien en anglais) a apporté des changements à la spécification JLS (Java Language Specification) qui ont grandement simplifié l'implémentation de certaines constructions couramment utilisées. Parmi ces changements figurent les classes internes et les classes anonymes. Lorsqu'elles sont utilisées correctement, elles peuvent faciliter la compréhension et la maintenance de votre programme. Examinons comment fonctionnent ces classes, comment les utiliser convenablement et comment éviter quelques erreurs courantes.
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La sérialisation permet de stocker l'état des objets, ainsi que la manière de recréer cet objet pour plus tard. Un objet peut ainsi exister entre deux exécutions d'un programme, ou entre deux programmes : c'est la persistance objet.

The main purpose of this lesson is to help you to understand the use of Java Action objects, with particular emphasis on the changes introduced in Java version 1.3. Along the way, you will also learn something about bound properties in Java.

Instead of giving you tips to use in your programming (at least directly), I want to look at some common mistakes made in enterprise programming. And instead of focusing on what to do, I want to look at what you should not do.

• It doesn't matter what data store type you use.
• Vendor-specific programming speeds up programming tasks.
• need an editor or tool to write my Enterprise JavaBeans
• I've got to include JMS, XML, JAXP, and more in every application.
• Stateful beans make programming more object-oriented.
• don't need anyone telling me what to do in my programming.

...In my opinion, creating one large actionPerformed() method and simply switching between the various action commands does not represent the best approach. I said such an approach doesn't follow good object-oriented (OO) design...

This article proposes an alternative to the standard Value Object/Data Transfer Object approach patterns, by illustrating using EJB 2.0 in conjunction with bean introspection and JAXP to create dynamic XML based data structures.
In the article, a framework is developed that can dynamically traverse the container managed persistent and related fields of a given local EJB and create an XML document that can be transferred between the various tiers in the application.

The Tech Tips covered :

• String Concatenation and Performance
• Improving Java I/O Performance

Note that performance results vary depending on environment. The results shown in these tips were obtained by the author -- you might see different results on your system...

This article focuses on the relative performance of these APIs :

• JAXP : Java API for XML Processing
• JAXB : Java API for XML/Java Binding
• Long Term JavaBeans Persistence
• JAXM : Java API for XML Messaging
• JAX RPC : Java API for XML RPC
• JAXR : Java API for XML Registry

These paradigm changes have greatly increased my power to express program logic, such that my programs have gotten smaller, simpler, and much easier to understand, while supporting ever-increasing user capabilities. When I started programming, I worked with simple command-line interfaces and text-based screen screens.?Next I produced fat-client?graphical user interfaces, and now I work on Web-enabled user interfaces. Again, each paradigm switch has greatly increased user power, flexibility, and ease of use while the code required to produce the interfaces has decreased and is much simpler to understand.

WeakHashMap is a type of Map which differs from other Maps in more than just having a different implementation.
WeakHashMap uses weak references to hold its keys, making it one of the few classes able to respond to the fluctuating memory requirements of the JVM. This can make WeakHashMap unpredictable at times, unless you know exactly what you are doing with it. In the following sections I examine how best to use WeakHashMap, and why WeakHashMap behaves the way it does.
Using WeakHashMap to Avoid Memory Leaks

Face it, software designers and developers rarely see eye to eye. Nowhere is this more evident than in the GUI development process, where designers take the lead, but often don't provide the type of information developers really need to bring their visions to life. Authors Renee Schwartz and Joe Winchester explain how Java layout managers can bring congruency to your GUI design and development process, by providing a common framework for both sides of the team to work with. Not only will this ease the friction between you, it could lead to better overall GUI design and a more robust final product.

This article will show you how to create a utility class that can seamlessly play a looped sample over and over in continuous loops, and which can replace the loop in realtime with another loop, without skipping a beat.