Java Program to Return the Largest Element in a List

Given a List, find the largest element in it. There are multiple approaches to tackle this problem like iterating through the List or using various inbuilt functions.

Input  : List = [5, 3, 234, 114, 154]
Output : 234

Input  : List = {10, 20, 4}
Output : 20

Approach 1: Using ForEach Loop

1. Create List object and store multiple elements in it.
2. Create one variable and initialize it with Integer.MAX_VALUE.
3. Start iterating through the List using for each loop and compare each element with the variable.
4. If the current element is greater than variable then update the variable.
5. At the end of the iteration, print the variable.

Below is the implementation of the above approach:

Java

// Java Program to Return the Largest Element in a List
import java.util.Arrays;
import java.util.List;

public class Test {

    public static void main(String[] args)
    {
        // List input
        List<Integer> arrayList
            = Arrays.asList(5, 3, 15, 234, 114, 1540);

        // Create maxValue variable and initialize with 0
        int maxValue = 0;

        // Check maximum element using for loop
        for (Integer integer : arrayList) {
            if (integer > maxValue)
                maxValue = integer;
        }
        System.out.println("The maximum value is "
                           + maxValue);
    }
}

Output

The maximum value is 1540

Approach 2: Using Iterators

1. Create List object and store multiple elements in it.
2. Create one variable and initialize it with Integer.MAX_VALUE.
3. Start iterating through the List using List iterator and compare each element with the variable.
4. If the current element is greater than variable then update the variable.
5. At the end of the iteration, print the variable.

Below is the implementation of the above approach:

Java

// Java Program to Return the Largest Element in a List
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

public class Test {

    public static void main(String[] args)
    {
        // List as input
        List<Integer> arrayList
            = Arrays.asList(5, 3, 15, 234, 114, 1540);
        // List iterator
        Iterator listIterator = arrayList.iterator();

        // Create maxValue variable and initialize with 0
        Integer maxValue = 0;

        // Iterate list
        while (listIterator.hasNext()) {
            Integer integer = (Integer)listIterator.next();

            // If value is greater then update maxValue
            if (integer > maxValue)
                maxValue = integer;
        }
        System.out.println("The maximum value is  "
                           + maxValue);
    }
}

Output

The maximum value is  1540

Approach 3: Using Indexing

1. Create List object and store multiple elements in it.
2. Create one variable and initialize it with Integer.MAX_VALUE.
3. Start iterating through the List and compare each element with the variable.
4. If the current element is greater than variable then update the variable.
5. At the end of the iteration, print the variable.

Below is the implementation of the above approach:

Java

// Java Program to Return the Largest Element in a List
import java.util.Arrays;
import java.util.List;

public class Test {

    public static void main(String[] args)
    {

        // List as input
        List<Integer> arrayList
            = Arrays.asList(5, 3, 15, 234, 114, 1540);

        // Create maxValue variable and initialize with 0
        Integer maxValue = 0;

        // Iterate List using for each loop
        for (int i = 0; i < arrayList.size(); i++) {

            // If element is greater the update maxValue
            if (arrayList.get(i) > maxValue)
                maxValue = arrayList.get(i);
        }
        System.out.println("The maximum value is "
                           + maxValue);
    }
}

Output

The maximum value is 1540

Approach 4: Using JDK 8

Java

// create maxValue variable and initialize with 0
import java.util.Arrays;
import java.util.List;

public class Test {

    public static void main(String[] args)
    {
        // List as input
        List<Integer> arrayList
            = Arrays.asList(5, 3, 15, 234, 114, 1540);

        // Initialize with inbuilt Max function
        int maxValue = arrayList.stream()
                           .max(Integer::compareTo)
                           .get();
        System.out.println("The maximum value is "
                           + maxValue);
    }
}

Output

The maximum value is 1540