An application client uses JNDI to look up and gain access to EJB components, resources, and environment properties defined in an XML deployment descriptor. You can code the application client like a standalone EJB client. However, since the application client is packaged with a deployment descriptor, you can alias the JNDI names used in code to different names when deploying to different servers.
An application client connects to an EAServer component using a JNDI environment naming context. Here is a simple implementation of an application client:
InitialContext initCntxt = new InitialContext(); Object acctRef = initCntxt.lookup(“java:comp/env/ejb/acctBean”); acctBeanHome home = (acctBeanHome) PortableRemoteObject.narrow(acctRef, acctBeanHome.class); Account acct = home.findByPrimaryKey(new AcctPK(1)); String name = acct.getName(); System.out.println(name);
The application client JAR file includes a deployment descriptor that defines the JNDI environment naming context entries. This example defines the EJB reference for an acctBean:
<application-client> <display-name>MyClient</display-name> <ejb-ref> <ejb-ref-name>ejb/AcctBean</ejb-ref-name> <ejb-ref-type>Entity</ejb-ref-type> <home>com.sybase.acct.acctBeanHome</home> <remote>com.sybase.acct.Account</remote> </ejb-ref> </application-client>
