OpenJPA to EclipseLink information and potential issues

The WebSphere Application Server Java Persistence 2.1 implementation for Java EE 7 is based on the EclipseLink implementation. You can continue to use the WebSphere Application Server JPA 2.0 implementation based on OpenJPA; however, this implementation will not be enhanced with JPA 2.1 functionality. This rule contains general information for migrating to Java EE 7 (OpenJPA), as well as information on issues that the WebSphere Migration Toolkit for Application Binaries (binary scanner) does not detect.

An automated fix exists for the following issues, which can be applied by copying the custom configuration to your application build file.

Before applying the automated fix, it is recommended to read through each issue to understand the potential impact on the application.

• Attributes with automatically generated values require configuration
• ElementCollection annotations must be accompanied by a defined Column annotation
• Embeddable classes cannot have an Id annotation when referenced by an EmbeddedId annotation
• Entity objects with constructors must also have a default constructor
• JoinColumn annotations must be used with relationship mappings
• Private accessor methods must have a Transient annotation
• Remove the Temporal annotation for some java.sql attributes
• Unannotated collection attributes require a Transient annotation
• Unannotated entity attributes require a Transient annotation

For information about this issue and other OpenJPA to EclipseLink migration issues, see the OpenJPA to EclipseLink JPA Migration: Mappings guide.