Question

The best way to filter a Java Collection

Answer 1

 this problem is solved using streams and lambdas in one line of code:

List<Person> beerDrinkers = persons.stream()
    .filter(p -> p.getAge() > 16).collect(Collectors.toList());

Use Collection#removeIf to modify the collection in place. 

persons.removeIf(p -> p.getAge() <= 16);