java中的平面图：真的需要lambda吗？

Question

Here is a code sample (form Mykong.com):

String[][] data = new String[][]{{"a", "b"}, {"c", "d"}, {"e", "f"}};

//Stream<String[]>
Stream<String[]> temp = Arrays.stream(data);

//Stream<String>, GOOD!
Stream<String> stringStream = temp.flatMap(x -> Arrays.stream(x));

If I understand it correctly, the lambda here is doing the actual flattening but could not flatMap understand what needs to do the flattening so that the lambda could be ommitted?

EDIT: Could flatMap have a default lambda used to convert in the "intuitive" way?

Answer 1

The lambda is not required, you can accomplish the same thing via a method reference. In practice the two approaches are identical though.

The last line could be:

Stream<String> stringStream = temp.flatMap(Arrays::stream);