java - What does "String[]::new" mean?

Question

I'm learning how to use stream, and I get a problem with this method.

public static String[] inArray(String[] array1, String[] array2) {
   return Arrays.stream(array1)
  .filter(str -> Arrays.stream(array2).anyMatch(s -> s.contains(str)))
  .distinct().sorted().toArray(**String[]::new**);
}

I'm so confused about String[]::new, could you give me a hint?

Answer 1

String[]::new means size -> new String[size].

When Stream#toArray(IntFunction<A[]> generator) is ready to produce an array, it calls generator and passes (generator.apply) the size of the inner collection to get a collection to fill it up.