Object identity is deceptively hard to implement correctly when objects are persisted to a database. However, the problems stem entirely from allowing objects to exist without an id before they are saved. We can solve these problems by taking the responsibility of assigning object IDs away from object-relational mapping frameworks such as Hibernate. Instead, object IDs can be assigned as soon as the object is instantiated. This makes object identity simple and error-free, and reduces the amount of code needed in the domain model.

Ad Server Beans are an open source ad server product written in Java using enterprise technologies. It is used for:

- creating banner ad campaigns and tracking their progress;

- targeting these campaigns to specific audience based on different criteria: site content, demographics, visitor geo location, time, etc.;

- serving ads to sites.

Despite the common belief it is actually possible to access private fields and methods of other classes via Java Reflection. It is not even that difficult. This can be very handy during unit testing. This text will show you how.

UMLGraph allows the declarative specification and drawing of UML class and sequence diagrams. The current features are part of an ongoing effort aiming to provide support for all types UML diagrams. An IEEE Software article titled On the declarative specification of models explains the rationale behind this approach. The tehnology behind UMLGraph was used to draw many of the diagrams appearing in the award-winning books Code Quality: The Open Source Perspective (Addison Wesley, 2006) and Code Reading: The Open Source Perspective (Addison Wesley, 2003). In addition, the UMLGraphDoc doclet included in this distribution automatically adds UML diagrams to javadoc documentation.

SDE for Eclipse supports a set of languages both in Code Generation and Reverse Engineering on Java, C++, CORBA IDL, PHP, XML Schema, Ada and Python. In addition, Code Generation supports C#, VB .NET, Object Definition Language (ODL), Flash ActionScript, Delphi, Perl, Objective-C, and Ruby. Reverse Engineering also supports Java class, .NET dll and exe, JDBC, and Hibernate mapping files.

Get a head start for your products by leveraging db4o's cutting edge technology to achieve unprecedented levels of performance and flexibility. Simply embed db4o's open source object database engine into your application and store and retrieve even the most complex object structures with only one line of code. Download a free version of db4o under the GPL license and start your free evaluation now!

Although it may seem trite to say it, $g(Object/Relational Mapping) is the Vietnam of Computer Science. It represents a quagmire which starts well, gets more complicated as time passes, and before long entraps its users in a commitment that has no clear demarcation point, no clear win conditions, and no clear exit strategy.

Gilead stands for Generic Light Entity Adapter. It permits you to send Persistent entities (and especiallay the partially loaded ones) outside the JVM (GWT, Flex, Web-Services, ...) without pain. No LazyInitialisationException. No DTO mapping. Just POJO and Domain Driven Design :) !

Hibernate is equipped with an extremely powerful query language that (quite intentionally) looks very much like SQL. But don't be fooled by the syntax; HQL is fully object-oriented, understanding notions like inheritence, polymorphism and association.

This document serves as a primer on financial math issues and as a tutorial on the use of BigDecimal in general and in OFBiz.