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Java Profiles

Subrahmanyam Allamaraju

Subrahmanyam is a Senior Engineer with BEA Systems. His interest in modeling lead him from his Ph.D. in Electrical Engineering to object-oriented programming, and then to distributed computing and software architecture. In this process, he drifted from his one-time home - the Indian Institute of Technology, to Computervision, and Wipro Infotech, and later to BEA systems. You can find more about his current activities at his hiome http://www.Subrahmanyam.com. 

In this exclusive interview, he talks with us about the Java 2 Platform Enterprise Edition (J2EE), and web technologies like JSP and ASP.

Read an review of his book

Q: What do you see as being the biggest change affecting the Java community in the last year?

A: One of the most significant changes is in the area of enterprise computing. While J2EE was introduced in 1998, J2EE began to occupy the center-stage of enterprise development in 2000. Over the last one year, the basic J2EE web and and EJB component models became more mature, and address more application development concerns. Simultaneously, the vendors are getting down to delivering more robust products. As a result, the focus of Java developers changed from J2SE to J2EE technologies such as Servlets, JSP pages, and EJBs. Another interesting development is that certain concepts such as transactions and security became more predominant in application development. I consider this a very sensible and desirable change.

Apart from this, the focus of J2EE is slowly expanding to reach the real enterprise via the connector API. The area is diverse and the problems are known to be difficult. J2EE developers should watch out for exploiting such developments.

Q: How do you find Java stacks up to other programming languages, such as C++ or scripting languages like ASP that are used to provide quick interfaces to databases and COM components?

I see two different questions – the first dealing with C++, and the other dealing with rapid development via scripting. With regards to the first question, I can only say that, Java is architecturally superior to other legacy programming languages.

The second question is quite interesting, as it deals with two different paradigms of application development. Any technology that lends to rapid development does so at the expense of separation of concerns and layering. Most of the scripting approaches fall under this category. This approach may not always be desirable. As an alternative, what I think important are application environments providing most of the commonly required infrastructure. J2EE meets this to a fair extent. Such environments allow rapid development by providing certain layers of facilities. I think this is a cleaner solution.

Q: For readers unfamiliar with enterprise development, what exactly is the Java 2 Platform Enterprise Edition? What does it mean for developers?

The most fundamental idea behind J2EE is that it is meant for server-side development. Server-side development is infrastructure intensive. On the server side, applications and data are typically distributed. Apart from this, resources are scarce, as resources are shared across a large number of clients. There are also the needs for security, transactions, legacy connectivity etc.

What J2EE addresses is the basic architecture and infrastructure required for server-side applications. Firstly, it includes a programming model and a set of APIs. The programming model consists of web (servlet and JSP) components, and EJB components. These are the basic development units in J2EE. The J2EE specifies how these components should be implemented.

Secondly, the J2EE specifies a set of commonly required enterprise APIs such as such as JDBC, JNDI, JMS, JTA etc. These APIs provide a very component centric integrated set of facilities to access services traditionally called as middleware. So, as opposed to using a proprietary API for asynchronous communication between two components, developers can use a generic API. The obvious advantage is that, most of the logic implemented in these components is independent of the underlying implementation. This gives J2EE a flavor of WORA.

The third important aspect of J2EE is its notion of packaging, and deployment. While software design process breaks down the architecture into bits and pieces of code, the idea of packaging gives the flexibility of building applications bottom-up – that is by assembling components into larger modules and applications. To me, this is a very important facility, and I think developers should consider this in their development plans.

Q: A reference implementation of J2EE is available for testing, but what about deployment of real-life projects? What type of application server would you recommend?

While reference implementations serve the purpose of validating the specs, I don’t consider reference implementations as development/deployment platforms. They are not meant to be so. I look for two basic aspects from a J2EE application server:

• Compliance to the specifications. I don’t think developers would like to have to surprises. When a product wants to add a non-standard feature, they should do it in such a manner that the spec-compliant behavior is still possible.
  

• Stability, robustness, and administration: As we move from experimental applications to large-scale production systems, only those products that provide a stable and robust platform with flexible administration facilities can stay longer in the market.

Q: In recent months there have been a few conflicts over licensing of J2EE and its direction. What’s your opinion over the licensing of the J2EE brand?

I think the issue has more or less been settled.

Q: The J2EE platform gives developers a lot of choice, with its wide range of technologies. How do developers choose RMI vs. CORBA, servlets vs. JSP?

Being a generic platform for enterprise systems, J2EE offers a wide range of choices. There are several questions that developers often face – such as entity vs session, CMP vs BMP, servlets vs JSP, messaging or no messaging. As J2EE gets richer in infrastructure, the number of choices is bound to increase.

My approach is that one has to take a very pragmatic view before going for one or the other. These choices have specific purposes, and one should consider a mix and match of these choices, leaving enough flexibility and maintainability in the architecture. While it is tempting to over-generalize a solution to a specific choice (such as JSP and sessions beans for all use cases and content), such an approach may not scale when it comes to maintainability.

I would also like to add that, what J2EE provides are the building blocks and associated APIs, and not architecture. J2EE is too generic to serve as a general-purpose architecture. One has still to develop application specific architectures on top of J2EE. Once the blocks of the architecture (and a context) are identified, it gets easier to make a choice between alternatives.

Q: Looking to the future now, where do you see Java heading? Is there a particular technology that you’re enthusiastic about?

To answer this question, let me go back to early 1996, when most of the developer community started experimenting with the Java language. I still recollect several articles and white papers expressing lot of ho(y)pe. Ultimately, what survived over the last four years is those Java technologies/approaches that fuelled mainstream internet-centric computing. Although I’m personally enthusiastic about wireless and device centric developments, I think most of challenges and demands are still in the middle-tier and back-end, particularly in the areas of inter-business integration, business-to-business integration etc. There is still some amount of hype here. I expect the existing initiatives to stabilize, and new initiatives towards standardization in these areas.

Q: Subrahmanyam Allamaraju, thank you for your thoughts on the Java 2 Enerprise Edition platform, and related technologies. Subrahmanyam's new book, a collaboration, is "Professional Java Server Programming J2EE Edition", and is published by Wrox Press.

Interview Copyright 2000 Wrox Press. Used with permission

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