The previous chapter examined the history and principles of Service-Oriented Architecture. It introduced a working definition of SOA:
SOA is an architecture of independent, wrapped business services communicating via published interfaces over a common middleware layer.
This chapter will explore the concept of middleware — a major element of the SOA story — by looking at both the theory behind it and some specific technologies that are common in the middleware universe. By the end of this chapter, readers should be able to understand the purpose, quirks, and landscape of middleware, and be able to distinguish its various features.
The first and most important thing to understand about middleware is ...