# How To Expose And Inject A POJO ...Into An EJB 3

A POJO:public class CustomResource{    public final static String JNDI_NAME = "theName";    public void doSomething(){        System.out.println("#Done !");    }}can be easily exposed (=bound to JNDI) with a singleton bean:@Startup@Singletonpublic class ResourceBinder {    @PostConstruct    public void bindResources(){        try {            Context context = new InitialContext();            context.rebind(CustomResource.JNDI_NAME, new CustomResource());            System.out.println("Resource bound...");            System.out.println(" " + context.lookup(CustomResource.JNDI_NAME));        } catch (NamingException ex) {            throw new IllegalStateException("Cannot bind resource " +ex,ex);        }    }}  ...and injected into a Stateless, Stateful, Singleton Bean or other resources like e.g. Servlets, Backing Beans etc:@Singleton@Startup@DependsOn("ResourceBinder")public class CustomResourceClient {    @Resource(mappedName=CustomResource.JNDI_NAME)    private CustomResource resource;    @PostConstruct    public void invokeResource(){        this.resource.doSomething();        System.out.println("----Resource invoked");    }} You should see the following output in the log files (tested with Glassfish v3b70):INFO: Portable JNDI names for EJB CustomResourceClient : [java:global/ResourceBinder/CustomResourceClient!com.abien.patterns.kitchensink.resourcebinder.CustomResourceClient, java:global/ResourceBinder/CustomResourceClient]INFO: Portable JNDI names for EJB ResourceBinder : [java:global/ResourceBinder/ResourceBinder, java:global/ResourceBinder/ResourceBinder!com.abien.patterns.kitchensink.resourcebinder.ResourceBinder]INFO: Resource bound...INFO:  com.abien.patterns.kitchensink.resourcebinder.CustomResource@50058560INFO: #Done !INFO: ----Resource invoked The ResourceBinder project was tested with NetBeans 6.8beta and Glassfish v3b70. It was pushed into: http://kenai.com/projects/javaee-patterns/.  Closing remarks:It is easier and better to declare a POJO as a Session Bean. You gain a lot with almost no trade-offs.You should be careful with the concurrency. Such an exposed POJO will be accessed by several threads / transactions concurrently.You easily inject POJOs with interceptors as well.You should never use System.out.println on the server in production, because of: public void println(String x) {	synchronized (this) {	    print(x);	    newLine();	}    } [See "Resource Binder" pattern, page 243,  in "Real World Java EE Patterns Rethinking Best Practices" book for more in-depth discussion]