how to fill two-dimensional arrays using lambda in java?

Regarding to documentation

Functional in nature. An operation on a stream produces a result, but does not modify its source. For example, filtering a Stream obtained from a collection produces a new Stream without the filtered elements, rather than removing elements from the source collection.

It returns a DoubleStream, which supports

sequential and parallel aggregate operations

This is why it not works.

Edit: The first section was incorrect. Replaced it by a more correct version