What are some advanced usages of the Java 8 Stream API?

What are some advanced usages of the Java 8 Stream API?

The Java 8 Stream API allows for functional-style operations on streams of elements. Advanced usages include parallel processing, custom collectors, and using streams with optional values.

Can you explain how to create a custom collector?

Sure! To create a custom collector, you need to implement the Collector interface. You define methods like supplier, accumulator, combiner, and finisher to specify how to collect elements.

What is the difference between map and flatMap?

The map function transforms each element in the stream, while flatMap flattens nested structures by applying a mapping function that returns a stream.

How can I use streams to filter and sort a list?

You can use the filter method to specify conditions and the sorted method to sort the elements. For example: list.stream().filter(x -> x > 10).sorted().collect(Collectors.toList());

Are there performance considerations when using streams?

Yes, while streams can improve readability and reduce boilerplate, they may introduce overhead. It's important to consider the size of the data and whether parallel streams are beneficial.