In one of our recent projects we have encountered some memory leaks using standard JavaEE technologies like CDI and EJBs. Our application in question does a lot of communication using JMS as a transportation layer. To be able to handle different message types dynamically we have used the Instance Injection of CDI. Using that approach with CDI might get your trapped into some memory leak problems like we did, so we would like to share our experiences and what you can do about it.
EJB
JBoss EAP / Wildfly – Three ways to invoke remote EJBs
The JBoss EAP / Wildfly application server provides as primary API the EJB client library to invoke remote EJB components. This client library is the implementation of the WildFly application server to invoke EJB components. The lookup of an object, such as a JMS connection factory, from the naming service is with the EJB client library not possible. For this purpose the remote naming implementation can be used. It can handle lookups of objects from the naming service. Both libraries can be used through the InitialContext of the JNDI API.
This post introduces three ways to configure the InitialContext to lookup and invoke EJB components, describes the pro and cons of each approach and introduces a combination of both libraries.
Monitoring the JBoss EAP / Wildfly Application Server with the Command Line Interface (CLI)
The JBoss EAP / Wildfly provides a powerful concept for management, configuration and monitoring of the JBoss Application Server itself and its Java EE Applications. The concept is based on the detyped management API. All management clients of the application server use this detyped management API to interact with the server.
In this post we focus on some useful runtime metrics which are of interest when monitoring your application server and application with the Command Line Interface (CLI).
Deployment Overlays: A new feature of the JBoss EAP 6.1
The Java EE platform provides a component-based architecture, which supports modular concepts to develop applications and reuse components in different applications and environments. Dependencies to the application server specific environment can be defined in deployment descriptors, such as ejb-jar.xml for EJB components.
How to access JSF from an EJB with JBoss Enterprise Application Platform 6 (aka JBoss AS7 / Wildfly)
The good old JBoss Seam framework introduced the usage of stateful session beans (SFSB) as backing beans for JSF applications. The trick was to bind the lifecycle of a SFSB to a web context, such as the session or the request context. Meanwhile this concept was integrated into the Java EE by the Context and Dependency Injection (CDI) specification. We really like to use SFSB in JSF because it provides a comfortable way to access the logic and persistence layer with an automatic and painless transaction management.
We also like to modularize our applications by separating its different layers into different Maven modules. Thus, usually the web and application logic are bundled as EJB archives, whereas the web pages are stored in a WAR archive. All modules are combined to an application as an EAR archive. In our opinion this approach is more maintainable than to mix everything into one big WAR archive.
Sometimes the web logic has to access JSF classes, i.e. to query the locale used in the current request. To do this with the JBoss EAP 6, a particularity must be taken into account. By default in the EAP6 only WAR archives containing a JSF descriptor have access to the JSF classes, EJB jars do not.
This is due to rules for implicit class loading dependencies which are added automatically by the application server at deployment time. To access JSF classes from an EJB archive, the EJB jar has to state an explicit dependency to the faces module. This is pretty simple, if you know how to do it.
Load-balancing and failover of remote EJB clients in EAP6 and JBoss AS7
In the recent posts of this series about the clustering capabilities of the JBoss EAP6 and the AS7, we covered the basic concepts, managing cluster nodes in domain mode and scalable HA cluster topologies. This post will be about clustering capabilities for remote EJB clients. We will explain how to cluster EJB components and invoke them from a standalone remote client with client-side failover and load balancing.
Clustering in JBoss AS7/EAP 6
Overview
The ability to combine different servers to a cluster that hides its internal servers from the clients and offers a virtual platform for an application is important for enterprise applications. It can be used to provide
- high scalability by adding cheap computational resources to the cluster on demand or
- high availability by using a transparent failover that hides faults within single servers.
Usually high scalability limits high availability and vice versa, but it is also possible to get both. The JBoss application server can be configured to support both features.
This post is the first one of a series about clustering with the JBoss AS 7. Here, we focus on the basic concepts behind JBoss AS 7 clustering and show you how to setup a basic clustered environment with a simple Java EE application.
In the series, we concentrate on the JBoss AS 7 respectively the EAP 6, which is the Red Hat-supported version of the JBoss application server. Future posts will be about particular subsystems of the JBoss AS, such as HornetQ or Infinispan.
Brave new world – Migrating a Java EE Application from JBoss AS 6 to JBoss AS 7
We are migrating an existing Java EE Application from JBoss AS 6 to JBoss AS 7. This blog post introduces our experience we have gained during the migration of the application to the new JBoss AS 7.
Overview of the application
The application is a Java EE application based on EJB, JPA and it contains a web application built with JSF. Furthermore, the application contains a web service to interact with a third-party system and some MBean’s for administration and configuration.
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