Adam Bien

Useful Production And Development Glassfish v3 JMS Monitoring Capabilities

admin — Wed, 4 Nov 2009 09:59:30 +0100

Glassfish v3 enables convenient monitoring of JMS destinations, directly from the web-based admin console. There are about 40 statistics available for each physical queue.

Some of them are: Number of Producers, Number of Consumers, Peak Number of Consumers, Number of Messages, Number of Messages Held in Transaction, Number of Messages Received, Number of Messages Sent, Peak Message Size etc.

To access the statistics open (in the admin console) the node: Java Message Service -> Physical Destinations the choose a destination and click on "View".

This new feature is very useful for debugging and performance monitoring of JMS applications (like tunguska :-)). Another reason to upgrade from Glassfish v2.

Sudden Death Of Enterprise Projects?

admin — Tue, 3 Nov 2009 11:26:32 +0100

It seems like the huge, data driven, projects are either somehow completed, or were replaced by standard solutions. Especially in tougher times, even big enterprises are interesting in saving money and build software in more pragmatic ways.

These are actually good news. Often (almost always) you can implement the same functionality with only a fraction of the originally planned resources, patterns, architecture, with a few passionated developers.

In the same time Java EE became leaner and leaner, so that it is particularly interesting for smallest projects. In the Java EE 6 release it is hard to find a superfluous artifact. Although projects became leaner, there is still need for transactions, persistency, remoting (e.g. over REST), and concurrency. Exactly that is already addressed by EJB 3.1 + JAX-RS + JPA 2.0.

The small / smallest projects in particular, are built with plain web container - with a considerable overhead. You have to install, sometimes implement, everything by yourself, without any benefit. You could argue that the result is leaner, but you should measure the results and compare it to a full "Java EE 5/6" stack.

I was asked in the recent few months, whether it is possible to install an EJB 3.1 container inside tomcat, just for out-of-the-box management of transactions / concurrency. You will find the answer here. On the other hand developers (I also) were surprised by e.g. Glassfish v3 incremental deployment capabilities - even method signature changes were recognized correctly. I'm already curious about JBoss 5.2.0 Java EE 6 capabilities...

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

admin — Mon, 2 Nov 2009 14:29:33 +0100

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

@Singleton

public 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@50058560

INFO: #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]

Oracle's Official NetBeans, Glassfish, VirtualBox Plans

admin — Fri, 30 Oct 2009 09:00:00 +0100

Some intentions are documented here.

Two Amazing NetBeans 6.8Beta Features

admin — Thu, 29 Oct 2009 09:00:00 +0100

1. NetBeans 6.8Beta generates Unit-Tests for EJB 3.1 with Embeddable Container code. It looks like:

@Test

public void testHello() throws Exception {

System.out.println("hello");

HelloService instance = (HelloService)javax.ejb.embeddable.EJBContainer.createEJBContainer().getContext().lookup("java:global/classes/HelloService");

String expResult = "";

String result = instance.hello();

assertEquals(expResult, result);

// TODO review the generated test code and remove the default call to fail.

fail("The test case is a prototype.");

}

This is a nice feature: you don't have to look-up the JNDI-name...

2. NetBeans is capable to auto-complete a bound item in the data table:

<h:dataTable id="hugo" value="#{newTweet.messages}" var="message">

<h:column>

<h:outputText value="#{message.content}"/> //the auto-completion works here!

</h:column>

</h:dataTable>

I tested NetBeans 6.8Beta in the last few days. It is stable, fast and especially interesting for Java EE 6 projects... Especially EJB 3.1 / JPA 2.0 support and JSF 2.0 editor were improved significantly....