Sun Java System Application Server Platform Edition 8.1 2005Q2 Update 2 Upgrade and Migration Guide

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# Migrating Enterprise EJB Modules

Application Server 6.x supports EJB 1.1, and the Application Server supports EJB 2.0. Therefore, both can support:

- Stateful or stateless session beans

- Entity beans with bean-managed persistence (BMP), or container-managed persistence (CMP)

EJB 2.0, however, introduces a new type of enterprise bean, called a message-driven bean (MDB).

J2EE 1.4 specification dictates that the different components of an EJB must be grouped together in a JAR file with the following structure:

- `META-INF/` directory with an XML deployment descriptor named `ejb-jar.xml`

- The `.class` files corresponding to the home interface, remote interface, the implementation class, and the auxiliary classes of the bean with their package

Application Server 6.x use this archive structure. However, the EJB 1.1 specification leaves each EJB container vendor to implement certain aspects as they see fit:

- Database persistence of CMP EJBs (particularly the configuration of mapping between the bean’s CMP fields and columns in a database table).

- Implementation of the custom finder method logic for CMP beans.

- Application Server 6.x andApplication Server 8.1do not handle migrations in the same way, which means that some XML files must be modified:

- The `<!DOCTYPE` definition must be modified to point to the latest DTD url (in the case of J2EE standard DDs, like `ejb-jar.xml)`.

- Replace the `ias-ejb-jar.xml` file with the modified version of this file (for example, file `sun-ejb-jar.xml`, which is created manually according to the DTDs). For more information, see http://wwws.sun.com/software/dtd/appserver/sun-ejb-jar_2_1-1.dtd

- Replace all the `<`ejb-name`>-ias-cmp.xml` files with one `sun-cmp-mappings.xml` file, which is created manually. For more information, see http://wwws.sun.com/software/dtd/appserver/sun-cmp-mapping_1_2.dtd

- Optionally, for CMP entity beans, use the capture-schema utility in the Application Server’s `bin` directory to generate the dbschema. Then place it above the `META-INF` directory for the entity beans.

## EJB Migration

As mentioned in Chapter 4, Understanding Migration, while Application Server 6.x supports the EJB 1.1 specification, Application Server also supports the EJB 2.0 specification. The EJB 2.0 specification introduces the following new features and functions to the architecture:

- Message Driven Beans (MDBs)

- Improvements in Container-Managed Persistence (CMP)

- Container-managed relationships for entity beans with CMP

- Local interfaces

- EJB Query Language (EJB QL)

Although the EJB 1.1 specification continues to be supported in the Application Server, the use of the EJB 2.0 architecture is recommended to leverage its enhanced capabilities.

For detailed information on migrating from EJB 1.1 to EJB 2.0, please refer to Chapter 5, Migrating from EJB 1.1 to EJB 2.0

## EJB Changes Specific to Application Server Platform Edition 8.1

Migrating EJBs from Application Server 6.x to Application Server 8.1 is done without making any changes to the EJB code. However, the following DTD changes are required.

### Session Beans

- The `<!DOCTYPE>` definition must be modified to point to the latest DTDs with J2EE standard DDs, such as `ejb-jar.xml`.

- Replace `ias-ejb-jar.xml` file with the modified version of this file, named `sun-ejb-jar.xml,`created manually according to the DDs. For more details, see http://wwws.sun.com/software/dtd/appserver/sun-ejb-jar_2_1-1.dtd

- In the `sun-ejb-jar.xml` file, the JNDI name for all the EJBs must be added before ”`ejb/`’ in all the JNDI names. This is required because, in Application Server 6.5, the JNDI name of the EJB can only be `ejb/<`ejb-name`>` where `<`ejb-name`>` is the name of the EJB as declared inside the `ejb-jar.xml` file.

  In the Application Server, a new tag has been introduced in the `sun-ejb-jar.xml`. This is where the JNDI name of the EJB is declared.

Note –

To avoid changing JNDI names throughout the application, declare the JNDI name of the EJB as `ejb/<`ejb-name`>` inside the `<`jndi-name`>` tag.

### Entity Beans

- The `<!DOCTYPE>` definition must be modified to point to the latest DTDs containing J2EE standard DDs, such as `ejb-jar.xml`.

- Update the `<cmp-version>` tag with the value 1.1, for all CMPs in the `ejb-jar.xml` file.

- Replace all the `<`ejb-name`>-ias-cmp.xml` files with the manually created `sun-cmp-mappings.xml` file. For more information, see http://wwws.sun.com/software/dtd/appserver/sun-cmp-mapping_1_2.dtd

- Generate `dbschema` by using the `capture-schema` utility in the Application Server installation’s bin directory and place it above `META-INF` folder for Entity beans.

- `Replace the ias-ejb-jar.xml` with the `sun-ejb.jar.xml` in Application Server.

- In Application Server 6.5, the finder's SQL was directly embedded into the `<`ejb-name`>-ias-cmp.xml`. In Application Server, mathematical expressions are used to declare the `<query-filter>` for the various finder methods.

### Message Driven Beans

Application Server provides seamless Message Driven Support through the tight integration of Sun Java System Message Queue with the Application Server, providing a native, built-in JMS Service.

This installation provides Application Server with a JMS messaging system that supports any number of Application Server instances. Each server instance, by default, has an associated built-in JMS Service that supports all JMS clients running in the instance.

Both container-managed and bean-managed transactions, as defined in the Enterprise JavaBeans Specification, v2.0, are supported.

Message Driven Bean support in iPlanet Application Server was restricted to developers, and used many of the older proprietary APIs. Messaging services were provided by iPlanet Message Queue for Java 2.0. An LDAP directory was also required under iPlanet Application Server to configure the `Queue Connection Factory` object.

The `QueueConnectionFactory`, and other elements required to configure Message Driven Beans in Application Server are now specified in the `ejb-jar.xml` file.

For more information on the changes to deployment descriptors, see Migrating Deployment Descriptors For information on Message Driven Beans see Using Message-Driven Beans in Sun Java System Application Server Platform Edition 8.1 2005Q2 Update 2 Developer’s Guide.

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