//s.charAt(0) = 'Z'; <-- It's not right. System.out.println(s.charAt(0)); System.out.println(s.charAt(1)); System.out.println(s.charAt(2)); System.out.println(s ...

NOTE: reverse() method is an instance method of StringBuilder class AND reverse() method is also an instance synchronized method of StringBuffer class in JAVA PLEASE NOTE THAT reverse() method is NOT ...