Java Stream How to - Peek a stream

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Question

We would like to know how to peek a stream.

Answer

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
//from w w  w . j  a  v a  2  s . c om
public class Main {
  public static void main(String[] args) {
    List<Integer> result = Stream.of(2, 3, 4, 5)
        .peek(x -> System.out.println("taking from stream: " + x))
        .map(x -> x + 17)
        .peek(x -> System.out.println("after map: " + x))
        .filter(x -> x % 2 == 0)
        .peek(x -> System.out.println("after filter: " + x))
        .limit(3)
        .peek(x -> System.out.println("after limit: " + x))
        .collect(Collectors.toList());
  
    System.out.println(result);
  }

}

The code above generates the following result.

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