Java流意外结果

Question

I have following code:

Stream.of("Java", "Stream", "Test")
      .peek(s -> System.out.print(s + " "))
      .allMatch(s -> s.startsWith("J"));

Why does it print me Java Stream?

Answer 1

allMatch is short-circuiting operation as most of the streams operations are. since allMatch returned early that's why peek is only printing the first two elements.

Answer 2

Because allMatch() checks if everyone element in the stream is true. And since the second was false, it doesn't have to check further.

So peek() won't print the 3rd element.