Packaging and Deploying Enterprise JavaBeans
The process of assembling components into modules, and modules into applications, is known as packaging. The Java ARchive (JAR) file format enables you to bundle multiple files into a single archive file. Enterprise beans use the JAR file format for packaging Enterprise JavaBeans in a generic and portable way.
The ejb-jar file is the standard format for packaging Enterprise JavaBeans. Figure 2.5 shows sample contents of an ejb-jar file. It contains deployment descriptor(s), one or more Enterprise bean classes, their home and component interfaces, and related files.
Figure 2.5. Standard ejb-jar file.
After you have packaged your Enterprise JavaBeans, you need to install and configure them in an EJB container for loading and execution. This is known as deployment, which makes the new functionality available as a service.
During deployment, you'll make several decisions, such as how clients find the components (naming, security, authorization), concurrency, data access (which component maps to which database objects, vendor/type of databases, JDBC drivers), which component lives where (partitioning), and which component participate in distributed transactions and which ones don't. Containers provide tools to help you with the deployment process.