Chapter 1. Java 8: why should you care?

 

This chapter covers

  • Why Java is changing again
  • Changing computing background: multicore and processing large datasets (big data)
  • Pressure to evolve: new architectures favor functional style over imperative
  • Introducing core new features of Java 8: lambdas, streams, default methods

Since the release of JDK 1.0 (Java 1.0) in 1996, Java has won a large following of students, project managers, and programmers who are active users. It’s an expressive language and continues to be used for projects both large and small. Its evolution (via the addition of new features) from Java 1.1 (1997) to Java 7 (2011) has been well managed. Java 8 was released in March 2014. So the question is this: why should you care about Java 8?

We argue that the changes to Java 8 are in many ways more profound than any other changes to Java in its history. The good news is that the changes enable you to write programs more easily—instead of writing verbose code like the following (to sort a list of apples in inventory based on their weight), 

Collections.sort(inventory, new Comparator<Apple>() {
    public int compare(Apple a1, Apple a2){
        return a1.getWeight().compareTo(a2.getWeight());
    }
});

in Java 8 you can write more concise code that reads a lot closer to the problem statement:

It reads “sort inventory comparing apple weight.” Don’t worry about this code for now. This book will explain what it does and how you can write similar code!

1.1. Why is Java still changing?

1.2. Functions in Java

1.3. Streams

1.4. Default methods

1.5. Other good ideas from functional programming

1.6. Summary