Using Collectors

Collectors in Java are a very powerful tool when you need to extract certain data points, descriptions, or elements from large data structures. They offer a very understandable way of describing what you want to do with a stream of elements, without needing to write complex logic.

There are a number of helpful default implementations of the Collector interface that you can start using easily. Most of these collectors will not allow null values; that is, if they find a null value in your stream, they will throw a NullPointerException. Before using a collector to reduce your elements in any of these containers, you should take care to handle null elements in the stream.

The following is an introduction to all default Collectors:

• toCollection: This generic collector will allow you to wrap your elements in any known class implementing the Collection interface; examples include ArrayList, HashSet, LinkedList, TreeSet, and others:

  List.of("one", &quot...