Use Streams to return Boolean if all the List values in a Map are empty/not-empty

Question

Given a Map mapping a String to a List, is there a way to use Java Streams to return a Boolean where TRUE means one or more list had elements? If all lists in the map were e

Answer 1

Stream::allMatch

In Java 8 you can check that not all lists are empty.

 boolean anyNonEmpty = !map.values().stream().allMatch(List::isEmpty);

Notice that Stream::allMatch is a short-circuiting terminal operation. So the stream is efficient, not running any longer than need be.