Welcome to JPO!

Welcome to the Java Persistent Objects (JPO) project site. This site is dedicated to Java developers attempting to find a simple solution to object persistence in a relational database (or object-relational mapping).

Get the latest download from SourceForge.

This site maintains a Wiki discussion on the topic of object persistence. Please join us! If you are unfamiliar with the Wiki concept, here are a couple of external links to get you started:

• The Wiki Book Site
• Ward Cunningham's Wiki Server

This project's goal is to be useful. Please offer your suggestions and/or comments by contacting me at tfredrich@users.sourceforge.net.

JPO Overview

JPO is a framework for persistence (storage and retrieval) of domain (or data) objects in Java-based database applications. The object/relational impedence missmatch is widely regarded as a complex problem with no easy solution.

JPO's mission is to be as simple as possible without requiring proprietary knowledge necessary for current O/R Mapping solutions, commercial or otherwise.

Love Your SQL

Most Java developers are already well versed in SQL usage through JDBC. JPO expands and embraces JDBC by using named SQL queries (in a properties file) to store and retrieve objects. No proprietary knowledge needed (or wanted)! Properties files and parameterized SQL--now you know JPO.

Transparent Data Access

JPO doesn't invade the domain model by forcing (or even ecouraging) domain objects to extend JPO classes. Consequently, object storage and retrieval is transparent from the domain model. Simply pass the object to the PersistenceManager and that's it!

Java Mapping

To map the attributes of a domain object, JPO uses a custom class (one per persistable object) to map the attributes onto the associated parameterized SQL statement(s).

SQL Inquiries

Queries are accomplished through a DataRequest object to simply hold parameters that get mapped to a parameterized SQL statement.

The Competition

Here are some other solutions to the O/R Mapping problem.

Free Software

Often, free stuff is worth what you pay for it. But free software? Now THAT's value!

• Castor
• COBRA
• Java Object Persistence (JOP)
• Osage
• Object Bridge (OJB)
• Artyom Rudoy's Persistence Layer

Commercial $oftware

If you'd rather buy into corporate rhetoric and positioning of commercial solutions, be my guest...

• TopLink
• Cocobase
• Sun's JDO Spec

Development Tools

These products are some of the best free software for developers.

• Eclipse IDE
• JEdit Source Editor
• The Gimp Graphics Editor
• Ant Build Tool
• Apache Web Server
• Tora Database Tool
• dia UML Drawing Tool
• JBoss Application Server
• JUnit Unit Testing Tool
• MySQL RDBMS
• Tomcat Servlet Engine
• WinCVS Windows CVS Client
• KDiff3 source compare (diff) tool
• Cygwin Windows command line