How to find maximum value from a list in java 8?

There is multiple way to find maximum value from a list in java 8.

• First convert Arrays to list using Arrays.asList() method.
• Now get the Stream data from List using arrayList.stream() method.

Using mapToInt() :- this method maps the stream elements into int. then max() method fetches the maximum elements.

Using reduce() :- this method combines elements into a single result. Inside Integer.max()   they check if a>b then prints a otherwise b.

Using max(Integer::compareTo) :- Integer::compareTo method compare two integer value and check value is greater than 0. through max() we find maximum value from that integer.

Using max(Comparator.naturalOrder()) :- Comparator.naturalOrder() method sort the elements in ascending order. then max method fetch the maximum value from this order elements.

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class MaxValueTest {
	public static void main(String[] args) {
		List<Integer> list = Arrays.asList(1, 3, 4, 5, 6, 7, 8, 8, 19);

		int maxValue1 = list.stream().mapToInt(Integer::intValue).max().getAsInt();
		System.out.println("using mapToInt to fetch max value :- " + maxValue1);

		int maxValue2 = list.stream().reduce(0, (a, b) -> Integer.max(a, b));
		System.out.println("Using reduce to fecth max value :- " + maxValue2);

		int maxValue3 = list.stream().max(Integer::compareTo).get();
		System.out.println("Using compareTo to fecth max value :- " + maxValue3);

		int maxValue4 = list.stream().max(Comparator.naturalOrder()).get();
		System.out.println("Using naturalOrder to fetch max value :- " + maxValue4);

	}
}

Output :-
using mapToInt to fetch max value :- 19
Using reduce to fecth max value :- 19
Using compareTo to fecth max value :- 19
Using naturalOrder to fetch max value :- 19