Java Fundamentals - Lesson 41 - Stream API Part 3

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[thethreestorms]

Laurent, are there any "clues" to look for in order to determine which operations are terminal? I did not see anything obvious in the code complete window. Such a shortcut may be useful for interview purposes like timed coding tests.
I am following your Spring security series on Friday and enjoying it.

[MateoEstudiante]

Hello, Laurent. Hope you're doing well. I have a question on the distinct intermediate operation of streams. I tried this code:

// The code is the next:
List<Cat> catList = List.of(new Cat(1), new Cat(1), new Cat(2));


// The Cat equals implementation is the next:
public boolean equals(Object obj) {
if (obj instanceof Cat cat) {
return cat.age - this.age == 0;
} else return false;
}

What happens is that, when printing, it still prints three objects, even knowing that there are two that are "equals" (the ones with age=1) according to the equals implementation. What is wrong with my code? Can you help me understand why this happens?

[iondodon-programare]

Hi, Laurentiu. Thank you for the lesson!

How are values passed through the pipeline? All together are being sent through the functions or each value separately is being sent (one by one)?

[aniket]

Hi, Laurentiu, can we perform the action with array using stream api which depends upon the position of the item in the list .. for example can we calculate sum of the diagonals of the 2d array using any of the stream API?

[ramihichri]

Hi @Laurentiu,

why do we have an exception here at the end?

Stream<Integer> numStream = Stream.of(10, 20, 30);
numStream.map(n -> n + 10).peek(s -> System.out.print(s));
numStream.forEach(s -> System.out.println(s));

many thanks for your effort