public class who extends Person { public who() { this("I am Tony"); public who(String str) { super(str); System.out.println("How do you do?"); public static void main(String[] args) { who new who("Tom"); public class Object Compare { public static void main(String[] args) { String oc = "hello"; Object ol = new String(oc); Object 02 - (Object) oc; if (01 = 0){ System.out.println("01-Oc"); if (02 - oc) { System.out.println("02--oc"); 1f (01.equals(oc)) { System.out.println("o1.equals(oc)--true"); if (02.equals(oc)) { System.out.println("o2.equals(oc)--true"); 5) class TestString? public void stringReplace (String text) { text - text.replace('j' , 'i'); text=text+"C"; public void bufferReplace (StringBuffer text) { text.setCharAt(0, '1'); text = text.append("C"); public void change(char ch[]) {