Java How To Program, Late Objects, 11th Edition

... Method setCharAt (lines 20 and 21) takes an integer and a character argument and sets the character at the specified position in the StringBuilder to the character argument. Method reverse (line 24) reverses the contents of the StringBuilder. Attempting to access a character that’s outside the bounds of a StringBuilder results in a StringIndexOutOfBoundsException.

Fig. 14.12 StringBuilder methods charAt, setCharAt, getChars and reverse

 1   // Fig. 14.12: StringBuilderChars.java
 2   // StringBuilder methods charAt, setCharAt, getChars and reverse.
 3
 4   public class StringBuilderChars {
 5      public static void main(String[] args) {
 6         StringBuilder buffer = new StringBuilder("hello there");
 7
 8         System.out.printf("buffer = %s%n", buffer.toString());
 9 System.out.printf( ...