Day 1. The Challenge of N-tier Development
The current trend in enterprise program development is to provide n-tier frameworks aimed at delivering applications that are secure, scalable, and available. This market has produced two competing products: Sun Microsystems' Java 2 Enterprise Edition (J2EE) and Microsoft Corporation's .NET Framework. Both products have similar features and capabilities and are designed to provide a software framework that simplifies the development and operation of medium- to large-scale enterprise-wide applications.
A full comparison of J2EE and .NET is beyond the scope of this book but it is useful to examine the different strategies used by the providers of these products. The .NET Framework is a product strategy from Microsoft and, not surprisingly, .NET is only available for Microsoft operating systems. J2EE, on the other hand, is platform-independent and so has advantages in heterogeneous environments.
Vendors such as IBM and BEA, among others, support the J2EE standard and provide commercial-grade J2EE development environments. The J2EE standard is actually an amalgamation of separate APIs and standards that are developed and ratified through an open framework overseen by the Java Community Process (JCP) (see Appendix B “The Java Community Process”).
The .NET Framework is under the sole control of Microsoft and lacks some of the integration and legacy features provided by J2EE. J2EE is a single language environment, namely Java. Tools are provided, as part of J2EE, to allow applications written in other languages to interoperate with a J2EE application, but these are primarily for legacy support. The .NET Framework is, in theory, language independent; in reality this means any language supported by Microsoft tools. Due to the omni-presence of Microsoft platforms and the portability and integration advantages of J2EE, it is likely that J2EE and .NET will share the market for Enterprise Application Development.
To understand the enterprise application market, this chapter investigates the principles of multiple tiers, component environments, and standards that underlie the frameworks. One of the objectives will be to give you a clear introduction of concepts and terminology used when discussing such frameworks.
The following are the major topics covered in today's lesson:
The pitfalls of monolithic software development
N-tier development as a model for enterprise computing
Introduction to J2EE, its components and services