Remove duplicate characters from the string

import java.io.*; class RemoveDupChar {     public static void main(String args[])throws IOException     {         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));         System.out.print("Enter any word : ");         String s = br.readLine();         int l = s.length();         char ch;         String ans="";                   for(int i=0; i<l; i++)         {             ch = s.charAt(i);             if(ch!=' ')                 ans = ans + ch;             s = s.replace(ch,' '); //Replacing all occurrence of the current character by a space         }        System.out.println("Word after removing duplicate characters : " + ans);     } }

Output:

Example 1:
Enter any word : Mississippi
Word after removing duplicate characters : Misp