java program to print the duplicate element of the array.

import java.util.*;

public class CountDuplicateElement {
public static void main(String[] args) {

    int arr[]=new int[]{1,3,4,5,2,1,3,4,5,6};
    int count,visited=-1;
    int fre[]=new int[arr.length];
    for(int i=0;i<arr.length;i++)
    {
      count=1;
      for(int j=i+1;j<arr.length;j++)
      {
        if(arr[i]==arr[j])
        {
          count++;
          fre[j]=visited;
        }
      }
      if(fre[i]!=visited)
          fre[i]=count;
    }
    for(int i=0;i<arr.length;i++)
    {
      if(fre[i]<=1)
      {
        continue;
      }
      else
      {
        System.out.println(arr[i]);
      }
    }

}
}