Functional Programming in Java

Chapter 3. Making Java more functional

This chapter covers

• Making standard control structures functional
• Abstracting control structures
• Abstracting iteration
• Using the right types

You now have all the types of functions you’ll need. As you saw in the previous chapter, these functions don’t require any exceptions to the traditional Java coding rules. Using methods as pure functions (a.k.a. functional methods) is perfectly in line with most so-called Java best practices. You haven’t changed the rules or added any exotic constructs. You’ve just added some restrictions about what functional methods can do: they can return a value, and that’s all. They can’t mutate any objects or references in the enclosing scope, nor their arguments. In the ...