7.9. Changes in EJB 1.1 Specification
Shortly before publication of this book, Sun released a public draft of Version 1.1 of the EJB specification. In this incremental release, Sun tightened up a few areas, changed its scheme for deployment descriptors, and made various other updates to the specification. The major updates are described below, followed by a short laundry list of the more significant changes.
7.9.1. XML-Based Deployment Descriptors
In EJB 1.1, the javax.ejb.deployment package is deprecated, and deployment descriptors for enterprise beans are composed using XML, instead of serialized DeploymentDescriptor objects. In the XML DTD defined in EJB 1.1, there's a clear separation of information regarding the structure of the enterprise bean(s) from information regarding the use of the beans in a particular application. The structural information for an enterprise bean includes components such as its various classes, environment variables the bean recognizes, and the container-managed fields (for entity bean). Application-specific information includes, for example, values for environment variables, the various client roles that are used for controlling access to beans, and permission settings for these various roles.
Similar to the deployment descriptors defined in EJB 1.0, these XML-based deployment descriptors are intended to include only structural information when a bean provider ships a collection of enterprise beans to application developers, and both structural information and application-specific information when an application provider ships an EJB-based application to an application deployer. The separation of these two types of information in the XML deployment descriptor makes this process more straightforward than under EJB 1.0.
The XML deployment descriptor for a set of enterprise beans can be provided separately or as part of an EJB-JAR file. In an EJB-JAR file, the deployment descriptor must be in the file META-INF/ejb-jar.xml.
7.9.2. Entity Beans Required
7.9.3. Home Handles
EJB 1.1 adds a new HomeHandle interface and a getHomeHandle() method on the EJBHome interface. A HomeHandle is a serializable reference to a home interface for an enterprise bean, analogous to the Handle interface, which represents a serializable reference to an EJB object. This allows a client to get a handle for a home interface and serialize it to some persistent storage, like a filesystem or database. The serialized HomeHandle can be deserialized later (in the same or another Java VM) and used to acquire a reference to the same home interface.
7.9.4. Detailed Programming Restrictions for Bean Implementations
EJB 1.1 lists detailed restrictions on what an enterprise bean implementation should avoid in its business methods in order to be portable across different EJB servers. These include rules against using sockets, creating class loaders, and including writable static fields on EJB implementation classes.
7.9.5. Assorted Other Changes
In addition to changes already listed, the following are some of the more significant updates introduced in the EJB 1.1 specification:
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