How do I take character array from user? I'm trying the below code to check whether character array consists of duplicate values or not.

public class dublicate 
{ 
	public static void isDuplicate(Character arr)
	{   int len=0;
		while(arr!=null)
		len++;
		Set<character> set=new HashSet<character>(Arrays.asList(arr));
		int len2=set.size();
		if(len==len2)
			System.out.println("array doesn't have duplicates");
		else
			System.out.println("yes they have duplicates\n");
		
	}
	public static void main(String args[])
	{
Scanner s=new Scanner(System.in);
System.out.println("enter elements in an array to check it contains duplicate elements or not\n");
Character arr[]=new Character[100];
for(Character c:arr)
	arr[c]=s.next().charAt(0);
}
}