Java Stream How to - Reduce to get the oldest person in the Person list

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Question

We would like to know how to reduce to get the oldest person in the Person list.

Answer

/* ww  w . jav a  2  s  .  c  om*/
import java.util.Arrays;
import java.util.List;

public class Main {

  public static void main(String[] args) throws Exception {
    List<Person> persons =
        Arrays.asList(
            new Person("Max", 18),
            new Person("Peter", 23),
            new Person("Pamela", 23),
            new Person("David", 12));   

    persons
    .stream()
    .reduce((p1, p2) -> p1.age > p2.age ? p1 : p2)
    .ifPresent(System.out::println);    // Pamela
  }

}
class Person {
  String name;
  int age;

  Person(String name, int age) {
      this.name = name;
      this.age = age;
  }

  @Override
  public String toString() {
      return name;
  }
}

The code above generates the following result.

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