code: public static String unescape(String string, char escape)
     {
        CharArrayWriter out = new CharArrayWriter(string.length());
        for (int i = 0; i < string.length(); i++)
        {
           char c = string.charAt(i);
           if (c == escape)
           {
              try
              {
                 out.write(Integer.parseInt(string.substring(i + 1, i + 3), 16));
              }
              catch (NumberFormatException e)
              {
                 throw new IllegalArgumentException(e);
              }
              i += 2;
           }
           else
           {
              out.write(c);
           }
        }
        return new String(out.toCharArray());
     }
docs: Unescapes string using escape symbol.
  
  @param string string
  @param escape escape symbol
  @return unescaped string