Object persistence is a must in almost all Java™ applications, from the desktop to the enterprise. The downside of persistence is that it has never been particularly simple. But that has changed with the most recent version of Simple Persistence for Java, an open source library for object-relational persistence. Simple Persistence for Java version 2.1.0 adds support for HSQLDB, a 100% pure Java database. Neither Simple Persistence for Java nor HSQLDB requires administration or configuration from the application user. Taken together, these tools enable you to introduce persistence to your applications with very little work. This article introduces you to Simple Persistence for Java v2.1.0 and shows you how to use it to achieve almost effortless object persistence in your Java applications.

When should an application use an embedded object database? Or, more precisely, when should a developer consider an embedded object database as an alternative to the more popular (and, probably, more familiar) relational database? This question is really two questions combined. The first is: when is it appropriate to use an ODBMS? The second is: assuming that you have determined to use an ODBMS, when is it appropriate to use an embedded one? (Many of the ODBMS systems mentioned above are available in both client/server and embedded forms.) In this article, I will deal with the individual, component questions separately. The combined answers will be the reply to the original question.

If you're a Java™ 2 Enterprise Edition (J2EE) developer, you'll want to preview the SQLXML technology. Check out procedures to create an XML document, store an XML document in a relational database, retrieve an XML document from a database, and navigate an XML document with the SQLXML Java data type.

The JSR 220 specification defines Enterprise JavaBeans 3.0. One of its primary goals is to simplify the creation, management, and storage of entity beans. Working towards that goal, Sun Microsystems and supporting community developers created a new application programming interface (API) that lets you use "plain old Java objects" or POJOs as your persistable entities. The Java Persistence API facilitates your use of POJOs as entity beans and significantly reduces the need for complicated deployment descriptors and extra helper beans. Additionally, you can even use the API in desktop applications.

When building Web applications with the Google Web Toolkit, using Berkeley DB Java Edition as a persistent data store can reduce project costs significantly.

HTML5 will reshape the web experience and line-of-business applications. With the offline capabilities and local persisted storage features, you can deliver the same rich user experiences online and offline that were previously available only in proprietary desktop application development frameworks. In this article, learn how to leverage HTML5 offline capabilities and local persisted storage features. An example application illustrates how to avoid common problems.

Many developers have asked how to use GWT and Hibernate together. Although you can find numerous discussions about this topic on the GWT Developer Forum, we thought it would be beneficial to sum up some of the most popular strategies, and highlight their advantages and shortcomings in the context of GWT application development.

Java developers can get a lot of mileage out of storing objects directly in an object-oriented database like db4o. Learn how db4o handles three concerns central to Java enterprise development: transactions, distributed data management, and Web application security.

Whereas the RDBMS uses SQL as its principal mechanism for finding and retrieving data, an OODBMS can use one of several different mechanisms. This second installment introduces a few of the options, including Query by Example and custom mechanisms unique to the OODBMS. As he explains, some of the alternatives can be easier to use than SQL itself.

It has been said that the database wars are over and the relational database won. However, anyone who believes this state of affairs has led to peace and prosperity among programmers hasn't tried using a relational database to back Java™ objects lately. This article is the first of an in-depth, multipart series introducing db4o, an object-oriented alternative to today's relational databases.