A Simple Data Access Layer using Hibernate
- Hibernate is a popular open source Object-Relational mapping tool. This article by Mario Aquino provides a quick introduction to get started with Hibernate.
- http://www.ociweb.com/jnb/jnbNov2003.html

Objective database abstraction layer (ODAL)
- A database persistence framework including query API, ORM, data validation/conversion, stored procedure support, code generation. Download and documentation are offered. [Open source, LGPL]
- http://odal.sourceforge.net/

ONJava.com: Object-Relational Mapping with Apache Jakarta OJB
- Charles Chan demonstrates OJB, an open source Java object persistence framework.
- http://www.onjava.com/pub/a/onjava/2003/01/08/ojb.html

ONJava.com: Don't Let Hibernate Steal Your Identity
- Typical means of establishing uniqueness and identity in databases, and thus Hibernate, don't necessarily suit Java's identity-oriented equals() and hashCode() methods. James Brundege has another idea for how to solve this problem.
- http://www.onjava.com/pub/a/onjava/2006/09/13/dont-let-hibernate-steal-your-identity.html

JGrinder
- Initially began as a solution for Object/Relational persistence. Supporting this involved the creation of many utility classes and tools that could be used to accelerate any application development effort. [Open source, LGPL]
- http://jgrinder.sourceforge.net/

Cayenne
- An Object-Relational mapping framework working with relational databases. [Open Source]
- http://cayenne.apache.org/

DODS (Data Object Design Studio)
- An Object-Relational Mapping Framework with a GUI Editor that lets you automatically create Java objects that map to relational databases. [Open Source, Mozilla-like]
- http://www.enhydra.org/tech/dods/

TopLink
- Object-relational bridge by Oracle. Quick tour, tutorials, and howtos. [Commercial]
- http://www.oracle.com/technology/products/ias/toplink/index.html

SimpleORM
- Implement, low overhead object/relational mapping on top of Java JDBC. [Open source]
- http://www.simpleorm.org/

JORM (Java Object Repository Mapping)
- The ObjectWeb open source adaptable persistence service. It is used to offer CMP 2.0 for the JOnAS server, as well as Speedo, a JDO implementation. [Open source, LGPL]
- http://jorm.objectweb.org/

Object-Relational Mapping
- Information and facts about object-relational mapping products, architecture problem-solving, and direction in product comparison and selection.
- http://www.service-architecture.com/object-relational-mapping/

iBatis
- XML-based Object/Relational mapping and persistence framework as well as a data access abstraction layer. [Open source]
- http://ibatis.apache.org/

Ammentos
- A lightweight persistence framework for Java (JDK5 or later). [Open source, GPL]
- http://ammentos.biobytes.it

Inductor
- A fully type-save, declarative ORQL for Hibernate, JDO, and EJB.
- http://www.certiv.net/products/inductor.html

DB Visual Architect
- An Object-Relational mapping tool. Generate persistent enable Java source from Class Diagram or ERD. A diagram editor is provided. It can generate code for client applications and server side applications. [Commercial]
- http://www.visual-paradigm.com/product/dbva/

Jaxor
- Simple and lightweight Object/Relational mapping and persistence framework. Configuration is stored in XML files and code generation relies on Apache velocity templates. [Open Source, Apache]
- http://jaxor.sourceforge.net/

Object Matter
- Provides an Object/Relational mapping tool with a persistence layer. Also features an introduction to Object/Relational mapping. [Commercial]
- http://www.objectmatter.com/

Hibernate
- An object/relational persistence and query service for Java. To support a rapid build procedure, Hibernate rejects the use of code generation or bytecode processing. Instead runtime reflection is used and SQL generation occurs at system startup time. [Ope
- http://www.hibernate.org/

FormPers
- A persistence framework with forms automation. It support on-the-fly SQL table creation/structure modification base on definition in Java class, automated form creation and automated form result parsing. [Freeware]
- http://www.jslope.com/formpers.html

JDBM
- A simple transactional persistence engine for Java. It can used to store a mix of objects and BLOBs, and all updates are done in a transactionally safe manner. JDBM also provides scalable data structures, such as HTree and B+Tree, to support persistence o
- http://jdbm.sourceforge.net/

CarrierWave
- Provides the following features: build generated client side data objects structurally mirroring server side business objects; pluggable persistence; pluggable binding between client and server; pluggable query mechanism; zero-configuration externalizatio
- http://carrierwave.sourceforge.net/

Torque
- An XML-based persistence layer. Part of the Apache Jakarta family. [Open Source, BSD-like]
- http://db.apache.org/torque/

Apache ObJectRelationalBridge - OJB
- A framework that provides transparent persistence of Java objects for JDBC-compliant RDBMS. Implements ODMG 3.0, JDO and uses XML-based O/R Mapping. [Open Source, LGPL]
- http://db.apache.org/ojb/

JDO vs. EJB by Gopalan Suresh Raj
- Compares and contrasts the Two Persistence Frameworks provided Java. Java Data Objects(JDO) which provides Language Transparent Orthogonal Persistence with Enterprise JavaBeans(EJB) that provides Functional Persistence.
- http://my.execpc.com/~gopalan/java/jdo/jdo_vs_ejb.html

J-Database Exchange (JDX)
- A cross-platform solution for transactional persistence of Java objects . By Software Tree, Inc. [Commercial]
- http://www.softwaretree.com/products/jdx/Jdx1.htm

Abra
- A Java library and a set of tools that can be used for storing and retrieving Java objects in a relational database. [Open source, BSD license]
- http://abra.sourceforge.net/

jStorm
- Simple tool for object-relational mapping, based on DbObjects, with mechanisms for aggregation and concurrency stamps. [Open Source, GPL]
- http://jstorm.sourceforge.net/

jRelationalFramework
- A lightweight framework that was written to automate the most tedious 80% of relational database access coding and leave the other 20% to the developer. [Open Source, MPL]
- http://jrf.sourceforge.net/

CocoBase Enterprise O/R
- Object/Relational mapping tool, with customized mappings for each major EJB server (including JBoss). [Commercial]
- http://www.thoughtinc.com/

Osage
- Object-Relational mapping for JDBC databases, with XML features. [Open Source, LGPL]
- http://osage.sourceforge.net/

DB Objects for Java
- Lightweight and flexible solution for storing and retrieving java objects into and from relational databases, without using SQL. [Open source, LGPL]
- http://dbobjects.sourceforge.net/

COBRA
- An object persistence layer written in Java which uses a relational database to provide persistent storage, whilst shielding programmers from the details of relational database access. [Open Source, GPL]
- http://www.kimble.easynet.co.uk/cobra/index.htm