Tyler Jewell

This is the second in a series of three articles discussing the clustering capabilities of BEA WebLogic Server 6.1 (WLS). This month we discuss replica-aware stubs, their impact on a clustered system, and how they're used with EJBs. How WebLogic Can Instrument EJBs WebLogic can provide clustering logic for an EJB in four possible locations (see Figure 1): The JNDI naming server, where the home stub is bound The container The home stub The remote stub The home stub and the remote stub are the most interesting aspects, since both of these objects are downloaded by a Java client and run within the JVM affiliated with the client, not the application server. WebLogic can develop load balancing and failover algorithms for EJBs not even resident in their own server! Given all of the locations where WebLogic can instrument one form of load-balancing or failover logic, the pe... (more)

Which Integration Approach is Best?

Recently I made a long trip to the East Coast. While there, I was able to meet with a number of developers, customers, and partners. I spoke to a variety of people and heard about a number of interesting community goings-on. Lately, I've been on a big Web services kick. I've spent a significant amount of time studying, speaking, and writing about this technology. While speaking to a number of different users groups in the area, I was surprised to see one question bubbling to the surface repeatedly. People kept asking about the difference between the J2EE Connector Architecture ... (more)

An introduction to WebLogic Server Clustering

Welcome to the first issue of BEA WebLogic Developer's Journal! This article is the first of a three-part series geared around the clustering capabilities of BEA WebLogic Server (WLS) 6.1 and aimed at introductory and advanced audiences. This article will talk about the importance of clustering and the high-level clustering capabilities of WLS, provide an in-depth analysis of HttpSession clustering and persistence, discuss basic configuration and trouble shooting, and provide an example that ties together everything discussed in this article. The second article will provide an in... (more)

The Business Transaction Protocol

By their very nature, Web services operate in a loosely-coupled, geographically-dispersed environ-ment. From an infrastructure perspective, what does this mean for transaction processing systems? Do the existing approaches to handling transactions through the use of an XA-compliant, two-phase commit transaction manager apply directly to Web services? Typical transaction manage-ment infrastructures have complete control over the resources that participate in a transaction: either every resource fully commits or fully rolls back. In a Web services environment, however, the resourc... (more)

The Impact Of EJB 2.0

Last summer, Sun Microsystems released the first public draft of the EJB 2.0 specification with a lot of fanfare. Since then, it's been through a whirlwind of discussion, controversy, and modifications. Yes, modifications. The latest release of the EJB specification is Public Final Draft 2, which was released at the end of April. The latest incarnation of the EJB specification has a variety of features that developers should become familiar with: The introduction of message-driven beans The creation of a new entity EJB container-managed persistence model A model for creating con... (more)