Scala for Java Developers

Book Preface

When I tell people around me that I now program in Scala rather than Java, I often get the question, “So, in simple words, what is the main advantage of using Scala compared to Java?” I tend to respond with this: “With Scala, you reason and program closer to the domain, closer to plain English”. Raising the level of abstraction is often the terminology employed to describe programs in a more readable and natural way for humans to understand rather than the zeros and ones understood by computers.

As computer systems that are encountered in telecom, manufacturing or financial applications mature and grow, different forms of complexity tend to emerge, which are as follows:
• Complexity due to the addition of supported features, for example, the variety of contract alternatives in an insurance system or the introduction of complicated algorithms to solve new challenges in our evolving society
• Complexity to offset the limitations of technologies; for instance, making a system distributed to handle larger loads or improve reliability and response time
• Accidental complexity, which is introduced because of factors other than the problem at stake, such as integration between legacy systems and not really compatible technologies, short-term workarounds to reach the consumer market in a quicker way, or misunderstanding how a large system is designed as a whole when many resources with different backgrounds and styles are contributing in a short period of time to a large code base

The third complexity is clearly unwanted and should be reduced to a minimum if not eliminated, whereas the other two should remain manageable. Scala tackles all of them, and the complexity of the business domain is something that will be manageable only if a system can be described in code as if it was described in well-written English.