What are Java collectors and how do they work?

Can you explain what Java collectors are?

Java collectors are part of the Stream API that allow you to accumulate elements from a stream into a collection like a List, Set, or Map.

How do I use collectors to join strings in Java?

You can use the Collectors.joining() method to concatenate strings from a stream. For example: String result = stream.collect(Collectors.joining(", "));.

What are some other useful collectors in Java?

Some useful collectors include Collectors.toList(), Collectors.toSet(), and Collectors.groupingBy(), each serving different purposes.

Can you give an example of grouping with collectors?

Sure! You can group elements by a property using Collectors.groupingBy(). For instance: Map<Category, List<Item>> groupedItems = items.stream().collect(Collectors.groupingBy(Item::getCategory));.