Finding the frequency of each element in an array.

Hint: Suppose we have the following array of numbers: [2, 3, 4, 2, 5, 3, 4, 2, 3, 5, 5].

After iterating through the array, we will have a frequency map that looks like this:

{2=3, 3=3, 4=2, 5=3}

Therefore frequency of each element in an array is 3

Here’s an example Java program that finds the frequency of each element in an array:

   import java.util.HashMap;

   import java.util.Map;

   public class FrequencyCounter {

    public static void main(String[] args) {

        int[] array = {1, 2, 3, 2, 4, 1, 5, 1};

        Map<Integer, Integer> frequencyMap = new HashMap<>();

        // Count the frequency of each element in the array

        for (int num : array) {

            if (frequencyMap.containsKey(num)) {

                frequencyMap.put(num, frequencyMap.get(num) + 1);

            } else {

                frequencyMap.put(num, 1);

            }
        }

        // Print the frequency of each element

        for (Map.Entry<Integer, Integer> entry : frequencyMap.entrySet()) {

            System.out.println("Element " + entry.getKey() + " occurs " + entry.getValue() + " time(s)");
        }
    }
}

In this program, we use a `HashMap` to store the frequency of each element in the `array`. We iterate over each element in the array and update the frequency accordingly. Finally, we iterate over the `HashMap` and print the frequency of each element.

When you run this program, it will output:

Element 1 occurs 3 time(s)

Element 2 occurs 2 time(s)

Element 3 occurs 1 time(s)

Element 4 occurs 1 time(s)

Element 5 occurs 1 time(s)

This indicates that the number 1 occurs 3 times, the number 2 occurs 2 times, and the numbers 3, 4, and 5 occur once each in the given array.