Thursday, July 25, 2013

WildFly 8.0.0.Alpha3 released with support for EJB invocations over HTTP

A week back we released WildFly 8.0.0.Alpha3 version. As usual the download is available on WildFly downloads page. This release comes within a month of the 8.0.0.Alpha2 release. Keeping up with the goals of WildFly 8, this new release contains additional EE7 support, certain bug fixes and also some WildFly specific features. The entire release notes are available here.

In this article, I'll provide some details about one of the WildFly features which has made into this release.

WildFly logo

WildFly ports

Traditionally, WildFly and previously named JBoss AS have opened different ports for different protocols and communication. For example, in the JBoss AS7 and now WildFly 8 series, by default the server opens the http port (which is by default 8080), remoting port (which is backed by JBoss Remoting and by default is 4447) and other such ports for usage by the applications deployed on the server. One of the goals of WildFly 8 (Final) is to have one single port open for all types of communication. This is meant to allow admins a better control of the server (firewall rules for example).

HTTP Upgrade support in Undertow

As some of you might know by now, the WildFly 8 series now uses Undertow as its web container. Undertow supports a standard feature called HTTP Upgrade. As can be read in that RFC, this feature allows the HTTP protocol to switch to a different protcol based on the presence of a header in the protocol data. This HTTP Upgrade feature acts as the backbone of the proposed "single port for communication" feature in WildFly.

EJB invocation over HTTP

Now that we have some background on HTTP Upgrade, let get to the details about the new feature that WildFly 8.0.0.Alpha3 introduces. Up until WildFly 8.0.0.Alpha2 (and previously in JBoss AS7 series) a project called JBoss Remoting has been the underlying protocol for remote communication with the server. The communication by default used to happen on the port 4447. Many of you will be familiar with this port, since this is what you used while looking up EJBs from a remote client.

Starting WildFly 8.0.0.Alpha3 (i.e. this new release), this port is no longer opened by WildFly by default. So how does one invoke EJBs or even use remote-naming (which too used this port) starting this version? The answer is simple, these remote clients will now have to use the HTTP port which by default is port 8080. The rest of the code will remain the same. This HTTP port is managed by the Undertow server which like I said earlier, has support for HTTP Upgrade. Internally, the EJB client API project (which is JBoss specific project dealing with remote EJB invocations) does the necessary plumbing to request Undertow to switch to JBoss "remoting" protocol while communicating on that HTTP port. Undertow then switches the protocol to "remoting" and the rest of the communication transparently happens as if it was the usual invocation on the remoting port.

So let's see some code to understand what exactly changes from previous version to the new version, from a remote client point of view. Let's take the example of the that's used to invoke EJBs. Earlier, you probably had:


# the server hostname/IP

# the port for communication

(and some other properties)

Starting this release, the only thing that changes is the port number in that properties, rest of it remains the same. So:


# the server hostname/IP

# the port for communication (the HTTP port)

So that's it from a typical client point of view.

For other new features and bug fixes, please take a look at the release notes.

Saturday, June 22, 2013

WildFly community members nominated for JBoss Community Recognition Award - voting open

Every year, JBoss community members are rewarded for their work in the community as part of the JBoss Community Recognition Awards (JBCRA). This year we have 2 community members from the WildFly project (previously known as JBoss Application Server) who have been nominated in 3 different categories.

Nicklas Karlsson has been nominated in the Issue/JIRA category and Stephen Coy has been nominated in 2 categories - Community Leadership and New Features. Please do vote for them here - it's just one page and takes less than a minute to vote. It's one way of thanking them for the help they have been providing in the community. Remember that these nominees are volunteers and are not Red Hat/JBoss employees so their contributions are that much more valuable.

The voting ends on July 26 2013. Don't wait for that date, vote now! :)

Monday, June 03, 2013

WildFly 8.0.0.Alpha1 release and a bit of history

It's been around 2 weeks now since we released WildFly 8.0.0.Alpha1 version. The download is available on the WildFly downloads page. I'm sure many of you might be wondering what WildFly is and some of you who are aware of what it is, might not be aware that there has been a release. I'll try and answer some of these questions and also add some details about what this release contains.

So what's WildFly?

WildFly is the new name for the community project which was previously known as JBoss Application Server. Late in 2012, we decided that we had to rename the community project, JBoss Application Server, to something else. As part of that (long drawn out) process, community members were asked to suggest new names and a few selected names were voted to select the new name. Ultimately, WildFly turned out to be the winner.

Why did we change the name?

JBoss Application Server (both the name and the project) has been a very popular project over the years. Initially when it started off, it was known simply as JBoss. Anytime anyone referred to the name JBoss, people knew that they were talking about the JBoss Application Server community edition. Over the years though, the reference started to get hazy. The community edition JBoss Application Server also has a paid and fully supported version known as JBoss Enterprise Application Platform (JBoss EAP). Notice the "JBoss" name in there? So there's JBoss Application Server community edition and then there's JBoss EAP paid version. It did not stop there! Over the years, various community projects hosted at started naming their projects with the name "JBoss" in it. So there was "JBoss ESB", "JBoss Transactions", "JBoss Messaging" and many such projects with the name "JBoss" in it. It's certainly no fault of those projects that they used "JBoss" as part of the name. It did make sense to use that name, since those projects were developed by JBoss community members. By the way, did you just notice the name "JBoss" even means a reference to the JBoss community as a whole?

So I guess at this point you might have realized where I'm headed with all this historical evidence. Clearly, the name "JBoss" had started to mean much more than just the JBoss Application Server community project. Although it was good thing from a brand point of view, it clearly wasn't too good from various other aspects. We had started seeing too much confusion about what each project/product stood for not just from a name point of view but also a release roadmap point of view. Take for example JBoss Application Server and JBoss EAP - users, typically those who are more busy with their application (rightly so) than trying to understand what each variant of project/product with the name "JBoss" in it meant, were just not sure which one to pick and which release of those had what features in it. Of course, it would take some explanation to help them understand this, but doing this on a regular basis was a clear sign that this isn't the right way forward.

So slowly during the past few years, there has been a conscious decision not to name new projects with "JBoss" in its name and also to rename some of the existing projects wherever possible. So for example, when "JBoss Messaging" project decided to release a completely new and better version, the project decided to name it "HornetQ". Similarly, JBoss Transactions is now known as Narayana. There are various examples of such renames and new names. Obviously, doing the same for JBoss Application Server would need some time and extra efforts since it was a really huge change for various reasons. But it had to be done ultimately and that's why it's now WildFly.

So what happens to the "JBoss" name in JBoss EAP?

The rename is only for the JBoss Application Server community edition. The paid version is still named JBoss Enterprise Application Platform (JBoss EAP). Since one of the original intentions of the rename was to clear the confusion between JBoss Application Server community edition and similar named JBoss EAP, the name change only applies to the community edition. So ultimately, over time, when someone refers to WildFly, we clearly know they are talking about the community project and very specifically the application server project.

How does WildFly 8.0.0.Alpha1 release relate to the previous JBoss AS7 releases?

WildFly 8.0.0.Alpha1 is the continuation of the release cycle of the application server community edition, which was previously known as JBoss AS7. The last release of JBoss AS7 was 7.1.1.Final (way back in March 2012) and WildFly 8.0.0.Alpha1 is now the next release of the same project with the new name.

Is WildFly 8.0.0.Alpha1 a release of a new project?

I know I already answered a variant of this question earlier, but I wanted to include the answer to this differently worded question too since I wanted it to be very clear that WildFly is just a rename of JBoss Application Server. It is not a new project. So WildFly 8.0.0.Alpha1 release is the continuation of the release cycle of the previously named JBoss Application Server project.

What's new in 8.0.0.Alpha1 release?

Now that we have addressed what WildFly is and a history around the name change, let's focus on the release itself. Some time back, Jason, the project lead of WildFly, listed down the goals of WildFly 8 release in the 2 dev mailing list threads here:
WildFly 8 Schedule -

So those are the goals and the schedule for WildFly 8.

WildFly 8.0.0.Alpha1 is the first milestone towards that. The release contains some of the new Java EE7 features, a new web server implementation named Undertow (as a replacement to JBossWeb web server) and some other new features. Of course, it also contains numerous bug fixes and since the previous release was more than a year back, the number of bug fixes are huge. Jason has summarized the WildFly 8.0.0.Alpha1 release in the dev mailing thread here

Please download this new version and give it a try. Like always, any feedback, questions or asking for help is always welcome in our WildFly user forums.

What's next for WildFly?

Like Jason noted in the WildFly 8 release schedule thread, we plan to push out a release almost every other month with the goal of having a 8.0.0.Final version at the end of this year. So, like with all the help that the community provided during AS7 releases:

Community help for JBoss AS 7.0 release -
Community help for JBoss AS 7.1 release -

please continue to do the same for WildFly releases.

In the coming weeks/months, we plan to blog more about the WildFly releases and the technologies that the WildFly runtime supports. In fact, Jason has asked in this dev mailing list thread whether the community members will be willing to blog too. That's another way of contributing too. So if you have any blogs that you have written or plan to write on WildFly, do let us know about it in that thread.
Those of you who want to try out the nightly builds of WildFly, can get it from our continuous integration job mentioned here

By the way, what's that image at the beginning of this article?

Thanks for noticing! That's the logo for WildFly which the team of artists (yeah, we do have team for that) helped us come up with :) Like it?

Tuesday, March 26, 2013

Java EE 7 and EJB 3.2 support in JBoss AS 8

 Update (June 10 2013): JBoss AS is now known as WildFly. This post was written before WildFly 8.0.0.Alpha1 was released. Any references to JBoss AS8 in this article should be considered as a reference to WildFly 8. Read my next article here which explains what WildFly is and why JBoss AS was renamed to WildFly.

Some of you might be aware that the Public Final Draft version of Java EE 7 spec has been released. Among various other new things, this version of Java EE, brings in EJB 3.2 version of the EJB specification. EJB 3.2 has some new features compared to the EJB 3.1 spec. I'm quoting here the text present in the EJB 3.2 spec summarizing what's new:

The Enterprise JavaBeans 3.2 architecture extends Enterprise JavaBeans to include the following new functionality and simplifications to the earlier EJB APIs:
  • Support for the following features has been made optional in this release and their description is moved to a separate EJB Optional Features document:
    • EJB 2.1 and earlier Entity Bean Component Contract for Container-Managed Persistence
    • EJB 2.1 and earlier Entity Bean Component Contract for Bean-Managed Persistence
    • Client View of an EJB 2.1 and earlier Entity Bean
    • EJB QL: Query Language for Container-Managed Persistence Query Methods
    • JAX-RPC Based Web Service Endpoints
    • JAX-RPC Web Service Client View

  • Added support for local asynchronous session bean invocations and non-persistent EJB Timer Service to EJB 3.2 Lite.

  • Removed restriction on obtaining the current class loader; replaced ‘must not’ with ‘should exercise caution’ when using the Java I/O package.

  • Added an option for the lifecycle callback interceptor methods of stateful session beans to be executed in a transaction context determined by the lifecycle callback method's transaction attribute.

  • Added an option to disable passivation of stateful session beans.

  • Extended the TimerService API to query all active timers in the same EJB module.

  • Removed restrictions on javax.ejb.Timer and javax.ejb.TimerHandle references to be used only inside a bean.

  • Relaxed default rules for designating implemented interfaces for a session bean as local or as remote business interfaces.

  • Enhanced the list of standard activation properties.

  • Enhanced embeddable EJBContainer by implementing AutoClosable interface.

As can be seen, some of the changes proposed are minor. But there are some which are useful major changes. We'll have a look at a couple of such changes in this article.

1) New API TimerService.getAllTimers()

EJB 3.2 version introduces a new method on the javax.ejb.TimerService interface, named getAllTimers. Previously the TimerService interface had (and still has) a getTimers method. The getTimers method was expected to return the active timers that are applicable for the bean on whose TimerService, the method had been invoked (remember: there's one TimerService per EJB).

In this new EJB 3.2 version, the newly added getAllTimers() method is expected to return all the active timers that are applicable to *all beans within the same EJB module*. Typically, an EJB module corresponds to a EJB jar, but it could also be a .war deployment if the EJBs are packaged within the .war. This new getAllTimers() method is a convenience API for user applications which need to find all the active timers within the EJB module to which that bean belongs.

2) Ability to disable passivation of stateful beans

Those familiar with EJBs will know that the EJB container provides passivation (storing the state of the stateful bean to some secondary store) and activation (loading the saved state of the stateful bean) capability to stateful beans. However, previous EJB versions didn't have a portable way of disabling passivation of stateful beans, if the user application desired to do that. The new EJB 3.2 version introduces a way where the user application can decide whether the stateful bean can be passivated or not.

By default, the stateful bean is considered to be "passivation capable" (like older versions of EJB). However, if the user wants to disable passivation support for certain stateful bean, then the user has the option to either disable it via annotation or via the ejb-jar.xml deployment descriptor.

Doing it the annotation way is as simple as setting the passivationCapable attribute on the @javax.ejb.Stateful annotation to false. Something like:

 @javax.ejb.Stateful(passivationCapable=false) // the passivationCapable attribute takes a boolean value  
 public class MyStatefulBean {  

Doing it in the ejb-jar.xml is as follows:

 <?xml version="1.0" encoding="UTF-8"?>  
 <ejb-jar xmlns=""  
       <!-- passivation-capable element takes either a true or a false value -->  

Two important things to note in that ejb-jar.xml are the version=3.2 attribute (along with the schema location) on the ejb-jar root element and the passivation-capable element under the session element.

So, using either of these approaches will allow you to disable passivation on stateful beans, if you want to do so.

Java EE 7 and EJB 3.2 support in JBoss AS8:

JBoss AS8 has been adding support for Java EE 7 since the Public Final Draft version of the spec has been announced. Support for EJB 3.2 is already added and made available. Some other Java EE 7 changes have also made it to the latest JBoss AS 8 builds. To keep track of the Java EE 7 changes in JBoss AS8, keep an eye on this JIRA

To use the already implemented features of Java EE 7 in general or EJB 3.2 in particular, you can download the latest nightly build/binary of JBoss AS from here. Give it a try and let us know how it goes. For any feedback, questions or if you run into any kind of issues, feel free to open a discussion thread in our user forum here.

Sunday, January 27, 2013

Custom error pages for expired conversations involving CDI and JSF

It's been a while since I last blogged. I keep thinking of blogging something technical but end up getting busy with other things. This last week there was a very interesting discussion at the coderanch forums. It was even more interesting because it involved JBoss :)

Developers familiar with Java EE web applications would know that the web application deployment descriptor (web.xml) allows you to specify "error pages" which the container will display when a specific exception (class) or a error code is thrown by the server for a web request. Here's a quick example of how it looks like:

   <!-- A custom error page for error code == 500 -->  
   <!-- A custom error page for exception type -->  

Simple enough - a couple of custom error pages defined for a specific error code and an exception type respectively. All of this works fine.

In current days, more and more programming models and frameworks come into picture while developing web applications. CDI and JSF are some of those. CDI has this concept of scopes (ex: request scope, session scope, application scope, conversation scope). We won't go into the details of what those are and when those are used, but let's consider conversation scope in this blog since that's what the discussion was about in the forum thread that prompted this blog.

So CDI allows multiple requests to be part of a "conversation scope". A conversation has a "start" and an "end", both of which can be managed by the application. When the application involves JSF, any conversation (id) gets auto-propagated to the JSF request(s). Apart from an explicit start/end demarcation of conversations, a conversation can also timeout. A request which refers to a conversation which has ended or timed out will run into an exception.

So we know have a bit of background on CDI conversation scope. So let's consider a case where the application wants to present a good looking page when the "conversation no longer present" exception is thrown (maybe because of a timeout). We have seen how to write a web.xml for error-page configurations - it would be as simple as:

   <!-- A custom error page for exception type org.jboss.weld.context.NonexistentConversationException -->  

Simple enough. The org.jboss.weld.context.NonexistentConversationException is the exception class type which gets thrown when the conversation has timed out (note that we are assuming that the web application is relying on Weld as the CDI spec implementation library). The above configuration works fine. The my-foo-bar-exception-page.html gets displayed when the org.jboss.weld.context.NonexistentConversationException is thrown.

BUT, let's now consider that we want to involve JSF in the error page just like the other parts of our application. So let's point the error-page to a URL pattern which maps to the JSF servlet:

   <!-- A custom error page for exception type org.jboss.weld.context.NonexistentConversationException -->  

Note that we changed the error page mapping to my-foo-bar-exception-page.xhtml (notice the xhtml extension) from my-foo-bar-exception-page.html. We'll again assume that the .xhtml resources are mapped to the JSF servlet so those requests are considered as JSF requests.

With this change to the web.xml, you'll notice that the my-foo-bar-exception-page.xhtml will no longer be displayed in you see a big stacktrace with repeatedly shows org.jboss.weld.context.NonexistentConversationException exception in the stacktrace thus giving an impression that the error-page configuration went wrong.

So what did we do wrong? Well, remember that earlier I mentioned that for JSF requests the conversation id gets propagated automatically. That's exactly what's happening here. The server notices the org.jboss.weld.context.NonexistentConversationException exception and then tries to render the error-page which is backed by JSF and since the conversation id gets propagated the server tries to find that non-existent conversation and ends up failing with the same org.jboss.weld.context.NonexistentConversationException and ultimately fails to render the error page. It's like going in circles to render that error page.

So how does one get past it? Keeping aside all the technical details, the obvious thing would be to not propagate the non-existent conversation id while rendering the (JSF backed) error page. So that's what we are going to do. CDI 1.1 (and Weld 1.1.2 and later) allows you to explicitly specify that a conversation shouldn't be propagated for a particular request. You can do this by passing along a parameter named "nocid" within that request. With that knowledge, let's now modify our web.xml to do the necessary changes so that our error page gets rendered properly:

   <!-- A custom error page for exception type org.jboss.weld.context.NonexistentConversationException.  
     Notice the "nocid" parameter being passed to make sure that the non-existent conversation id  
     isn't passed to the error page  

Notice that we are passing the "nocid" parameter as part of the query string of the error page location. The value for "nocid" parameter really doesn't matter but for the sake of keeping that value logical, we have used the value "true" here. Once this change is done, you'll start noticing that the error page (backed by JSF) now renders correctly!

It took a while for us to get to this solution in that forum thread because it looked so simple that it should have "just worked", but it didnt' Here's the forum thread at coderanch that I've been talking about. Credit goes to Greg Charles for figuring out how to pass that nocid parameter.