Overview
An entity bean is defined as a representation of persistent data that has the ability to read from database and populate its fields with data. It can be updated and stored back to the database. There are two types: Bean-Managed Persistence(BMP) and Container-Managed Persistent(CMP). This article covers the migration of a BMP sample application. For this type of entity bean, actual code must be written to handle persistent operations such as loading, saving and finding data. The developer must use persistence API such as JDBC to select, insert, update, delete from a database.
This article is organized in the following sections:
- BMP implementation analysis
- Sample application
- The JBoss environment
- The Geronimo environment
- Step-by-step migration
- Summary
BMP implementation analysis
BMP implementation may vary from one vendor to another. The purpose of this section is to provide a BMP specific feature-to-feature comparison between JBoss v4 and Apache Geronimo so you can clearly identify the differences and plan accordingly before migration.
Features |
JBoss v4 |
Geronimo |
---|---|---|
EJB Container |
JBoss comes with its own EJB Container implementation. |
Geronimo uses OpenEJB as its EJB Container. |
JMS implementation |
JBoss is packaged with JBoss MQ. |
Geronimo uses ActiveMQ as its JMS implementation. |
Sample application
The Loan BMP application is very simple. When the command line client is run, an entry is made into the database. The findByPrimaryKey() method of the CustomerHomeRemote interface is called and the field values of the returned CustomerRemote object are printed to the console. This is followed by a call to the findBySssNo() method after which the field values of the returned CustomerRemote object are printed to the console.
The following figure illustrates the application flow: