Introduction

In this demo I have used NetBeans IDE 8.2 for debugging purpose. But you can use any java programming language compiler as per your availability..

import java.util.Arrays; 
public class Javaexcercise {
  public static void main(String[] args) 
    {
        int[] my_array = {1, 2, 3, 4, 5, 6, 7, 2, 3, 4};
 
        for (int i = 0; i < my_array.length-1; i++)
        {
            for (int j = i+1; j < my_array.length; j++)
            {
                if ((my_array[i] == my_array[j]) && (i != j))
                {
                    System.out.println("Duplicate array element : "+my_array[j]);
                }
            }
        }
    }    
}

Result