Java Platform, Enterprise Edition (Java EE) 8 The Java EE Tutorial

## Packaging Enterprise Beans

This section explains how enterprise beans can be packaged in EJB JAR or WAR modules. It includes the following sections:

- Packaging Enterprise Beans in EJB JAR Modules

- Packaging Enterprise Beans in WAR Modules

### Packaging Enterprise Beans in EJB JAR Modules

An EJB JAR file is portable and can be used for various applications.

To assemble a Java EE application, package one or more modules, such as EJB JAR files, into an EAR file, the archive file that holds the application. When deploying the EAR file that contains the enterprise bean’s EJB JAR file, you also deploy the enterprise bean to GlassFish Server. You can also deploy an EJB JAR that is not contained in an EAR file. Figure 5-2 shows the contents of an EJB JAR file.

Figure 5-2 Structure of an Enterprise Bean JAR

### Packaging Enterprise Beans in WAR Modules

Enterprise beans often provide the business logic of a web application. In these cases, packaging the enterprise bean within the web application’s WAR module simplifies deployment and application organization. Enterprise beans may be packaged within a WAR module as Java programming language class files or within a JAR file that is bundled within the WAR module.

To include enterprise bean class files in a WAR module, the class files should be in the `WEB-INF/classes` directory.

To include a JAR file that contains enterprise beans in a WAR module, add the JAR to the `WEB-INF/lib` directory of the WAR module.

WAR modules that contain enterprise beans do not require an `ejb-jar.xml` deployment descriptor. If the application uses `ejb-jar.xml`, it must be located in the WAR module’s `WEB-INF` directory.

JAR files that contain enterprise bean classes packaged within a WAR module are not considered EJB JAR files, even if the bundled JAR file conforms to the format of an EJB JAR file. The enterprise beans contained within the JAR file are semantically equivalent to enterprise beans located in the WAR module’s `WEB-INF/classes` directory, and the environment namespace of all the enterprise beans are scoped to the WAR module.

For example, suppose that a web application consists of a shopping cart enterprise bean, a credit card–processing enterprise bean, and a Java servlet front end. The shopping cart bean exposes a local, no-interface view and is defined as follows:

    package com.example.cart;

    @Stateless
    public class CartBean { ... }

The credit card–processing bean is packaged within its own JAR file, `cc.jar`, exposes a local, no-interface view, and is defined as follows:

    package com.example.cc;

    @Stateless
    public class CreditCardBean { ... }

The servlet, `com.example.web.StoreServlet`, handles the web front end and uses both `CartBean` and `CreditCardBean`. The WAR module layout for this application is as follows:

    WEB-INF/classes/com/example/cart/CartBean.class
    WEB-INF/classes/com/example/web/StoreServlet
    WEB-INF/lib/cc.jar
    WEB-INF/ejb-jar.xml
    WEB-INF/web.xml

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