Java 8– Find first and all longest strings in List

By Atul Rai | Last Updated: November 28, 2023 Previous       Next

In Java 8, you can find the first and all longest strings from a list using the Stream API along with the max function. Here’s an example:

1. Find first longest string

// Find the book has max length
String max1 = books.stream().max(Comparator.comparing(String::length)).get();

//OR
String max2 = Collections.max(books, Comparator.comparing(String::length));

2. Find all longest strings

// Find all books have max length
List<String> maxAll = books.stream().collect(Collectors.groupingBy(String::length))
        .entrySet().stream().max(Map.Entry.comparingByKey())
        .map(Map.Entry::getValue).get();

//OR
int maxLength = books.stream().mapToInt(String::length).max().orElse(0);
List<String> maxAll2 = books.stream().filter(s -> s.length() == maxLength)
        .collect(Collectors.toList());

Similar Post: Java 8– Find first and all smallest string in List

See the complete example.

package org.websparrow;

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class MaxLenOfBook {

    public static void main(String[] args) {

        List<String> books = Arrays.asList("Gaban", "Ramayan", "Bhagavat Gita", "Wings Of Fire", "Godan");

        // Find the book has max length
        String max1 = books.stream().max(Comparator.comparing(String::length)).get();
        System.out.println(max1);
        //OR
        String max2 = Collections.max(books, Comparator.comparing(String::length));
        System.out.println(max2);

        // Find all books have max length
        List<String> maxAll1 = books.stream().collect(Collectors.groupingBy(String::length))
                .entrySet().stream().max(Map.Entry.comparingByKey())
                .map(Map.Entry::getValue).get();
        System.out.println(maxAll1);
        //OR
        int maxLength = books.stream().mapToInt(String::length).max().orElse(0);
        List<String> maxAll2 = books.stream().filter(s -> s.length() == maxLength)
                .collect(Collectors.toList());
        System.out.println(maxAll2);
    }
}

Output:

Bhagavat Gita
Bhagavat Gita
[Bhagavat Gita, Wings Of Fire]
[Bhagavat Gita, Wings Of Fire]

References

1. Java 8 – Count the Occurrences of Character in String
2. Java Collections.min() and Collections.max() Methods