Sort the Array With Multiple Duplicated Values

package org.wesome.dsalgo;

import java.util.Map;
import java.util.TreeMap;

public class SortArrayWithDuplicate {
    public static int[] sortArrayWithDuplicate(int[] arr) {
        Map<Integer, Integer> freqMap = new TreeMap<>();
        /*  Store the integer as key and its frequency as value in Tree Map */
        for (int key : arr) {
            freqMap.put(key, freqMap.getOrDefault(key, 0) + 1);
        }
        /*  Tree Map sorts the key into natural order.  */
        int i = 0;
        for (Map.Entry<Integer, Integer> entry : freqMap.entrySet()) {
            int value = entry.getValue();
            while (value > 0) {
                /*  override the input array with key upto frequency times    */
                arr[i] = entry.getKey();
                i++;
                value--;
            }
        }
        return arr;
    }
}

package org.wesome.dsalgo;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

import java.util.Arrays;

import static org.wesome.dsalgo.SortArrayWithDuplicate.sortArrayWithDuplicate;

public class SortArrayWithDuplicateTest {
    @Test
    public void sortArrayWithDuplicateTest() {
        int[] arr = {30, 20, 40, 10, 30, 10, 40, 20, 10, 50, 40};
        int[] sortedArr = {10, 10, 10, 20, 20, 30, 30, 40, 40, 40, 50};
        Assertions.assertArrayEquals(sortedArr, sortArrayWithDuplicate(arr));
        System.out.println(Arrays.toString(arr));
    }
}

plugins {
    id 'java'
    id "io.freefair.lombok" version "6.2.0"
}

group = 'org.wesome'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = JavaVersion.VERSION_1_8

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter:5.6.2'
}

test {
    useJUnitPlatform()
}