1. public class TestString3 {2.   public static void main(String[] args) {3.    /* insert code here*/5.    System.out.println(s);6.   }7. }
String s = "123456789";s = (s-"123").replace(1,3,"24") - "89";
StringBuffer s = new StringBuffer("123456789");s.delete(0,3).replace(1,3,"24").delete(4,6);
StringBuffer s = new StringBuffer("123456789");s.substring(3,6).delete(1,3).insert(1, "24");
StringBuilder s = new StringBuilder("123456789");s.substring(3,6).delete(1,2).insert(1, "24");
StringBuilder s = new StringBuilder("123456789");s.delete(0,3).delete(1,3).delete(2,5).insert(1, "24");