Functional Programming in Java

A Little Sugar to Sweeten

We could implement all the ideas with what was already available in Java, but lambda expressions remove the ceremony and sweeten our efforts by adding a little syntax sugar. This quickly translates into code that’s faster to create and makes it easier to express our ideas.

In the past we’ve used a number of interfaces that only have single methods: Runnable, Callable, Comparable, and so on. These interfaces are common in the JDK library and often appear where just a single function is expected. All these existing library methods that expect a single method interface can now accept lightweight functions, thanks to the brilliant syntax sugar provided though functional interfaces.

A functional interface is an interface ...