Find if the characters in the given string are unique & not repeating. If the string has all the unique characters then replace the spaces with %20 & print the changed string.
Example : If the given string is abcd yu then output will be -
true
abcd%20yu

If the given string is abcda yu then the output will be -
false

import java.lang.reflect.Field;
public class Unique {
 public static void main(String[] args) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException {
  String str = "abcda yu";
  Field fStr = String.class.getDeclaredField("value");
  fStr.setAccessible(true);
  char[] chr = (char[])fStr.get(str);
  char[] chr1 = new char[chr.length+2];
  int checker = 0;
  int j = 0;
  for (int i = 0; i < str.length(); ++i) {
   int val = str.charAt(i) - 'a';
   if(str.charAt(i) == ' ') {
    chr1[j] = '%';
    chr1[++j] = '2';
    chr1[++j] = '0';    
   } else {
    chr1[j] = chr[i];    
   }
    j++;
   if ((checker & (1 << val)) > 0) {
    System.out.println(false);
    System.exit(0);
   }
   checker |= (1 << val);
  }
  fStr.set(str, chr1);
  System.out.println(true);
  System.out.println(str);
 }
}