Check whether array has all identical elements using Arrays.asList() and HashSet in Java Last Updated : 18 Jun, 2019 Summarize Comments Improve Suggest changes Share Like Article Like Report Given an array arr[] of N elements, the task is to check whether the array have all same (identical) elements or not without using the loop. If all elements are same then print Yes otherwise print No. Examples: Input: arr[] = {2, 2, 2, 2, 2} Output: Yes The given array has all identical elements i.e. 2. Input: arr[] = {2, 3, 3, 3, 3, 2, 2} Output: No Approach: First, we check the size of array if the size of an array is 0 or 1 then the array is identical. If it's size is > 1 then we take a set and copy all elements of an array in a set using Arrays.asList(). Then we calculate the size of the set, if the size of the set is 1, then the array has all identical elements otherwise not. Below is the implementation of the above approach: Java // Java implementation of the approach import java.util.*; class GFG { // Generic function to check whether the given array // has all identical element or not public static <T> void checkIdentical(T array[]) { // Create the Set by passing the Array // as parameter in the constructor Set<T> set = new HashSet<>(Arrays.asList(array)); // Check the size of set, f size is 0 or 1 then // array has only identical elements if (set.size() == 1 || set.isEmpty()) { System.out.print("Yes"); } else { System.out.print("No"); } } // Driver code public static void main(String args[]) { Integer arr[] = { 2, 2, 2, 2, 2, 2 }; checkIdentical(arr); } } Output: Yes Comment More infoAdvertise with us Next Article Check whether array has all identical elements using Arrays.asList() and HashSet in Java R rajput-ji Follow Improve Article Tags : Java Java-Arrays java-hashset Practice Tags : Java Similar Reads How to Check whether Element Exists in Java ArrayList? Java ArrayList is a resizable array, which can be found in java.util package. We can add or delete elements from an ArrayList whenever we want, unlike a built-in array. We can check whether an element exists in ArrayList in java in two ways: Using contains() methodUsing indexOf() method Method 1: Us 2 min read All elements in an array are Same or not? Given an array, check whether all elements in an array are the same or not. Examples: Input : "Geeks", "for", "Geeks" Output : Not all Elements are Same Input : 1, 1, 1, 1, 1 Output : All Elements are Same Method 1 (Hashing): We create an empty HashSet, insert all elements into it, then we finally s 5 min read Difference between ArrayList and HashSet in Java Here are couple of differences between ArrayList and HashSet. Inheritance: Implementation: Implementation : ArrayList implements List interface while HashSet implements Set interface in Java.Internal implementation: ArrayList is backed by an Array while HashSet is backed by an HashMap.Duplicates : A 3 min read Check If a Value is Present in an Array in Java Given an array of Integers and a key element. Our task is to check whether the key element is present in the array. If the element (key) is present in the array, return true; otherwise, return false.Example: Input: arr[] = [3, 5, 7, 2, 6, 10], key = 7Output: Is 7 present in the array: trueInput: arr 8 min read Remove repeated elements from ArrayList in Java Prerequisite: ArrayList in Java Given an ArrayList, the task is to remove repeated elements of the ArrayList in Java. Examples: Input: ArrayList = [1, 2, 2, 3, 4, 4, 4] Output: [1, 2, 3, 4] Input: ArrayList = [12, 23, 23, 34, 45, 45, 45, 45, 57, 67, 89] Output: [12, 23, 34, 45, 57, 67, 89] Below are 3 min read Like