InvalidUserInputException

Question

hey folks,
I am studying the Horton's Java 2 and experiencing an error in chapter 13:
the compiler says the InvalidUserInputException is never thrown in body of my try statement. But I have the in.readInt() which might throw this error. I have the readInt() defined in class "FormattedInput".
I will copy paste the code for the PhoneNumber.java and then FormattedInput.java.
please help me find what is wrong here. Thanks.
import java.io.*;
import java.util.*;
class PhoneNumber implements Serializable{
    public void addEntry(BookEntry entry){
        phonebook.put(entry.getPerson(), entry);
    public BookEntry getEntry(Person key){
        return(BookEntry)phonebook.get(key);
    public PhoneNumber getNumber(Person key){
        return getEntry(key).getNumber();
    private HashMap phonebook = new HashMap();
    public static PhoneNumber readNumber(){
        FormattedInput in = new FormattedInput();
        int maxTries = 5;
        String area = null;
        String localcode = null;
        for (;;){
            try{
                if (area == null){
                    System.out.println("\nEnter the area code: ");
                    area =  Integer.toString(in.readInt());
                if (localcode == null){
                    System.out.println("Enter the local code:");
                    localcode =  Integer.toString(in.readInt());
                System.out.println("Enter the number:");
                String code =  Integer.toString(in.readInt());
                localcode += " " + code;
                return new PhoneNumber(area, localcode);
            }catch(InvalidUserInputException e){
                if (--maxTries == 0){
                    System.out.println("Maximum number of errors exeeded Termination!");
                    System.exit(1);
                System.err.println(e.getMessage() + "\nTry again");
                continue;
    public PhoneNumber(String areacode, String number){
        this.areacode = areacode;
        this.number = number;
    public String toString(){
        return areacode + ' ' + number;
    private String areacode;
    private String number;
and now the FormattedInput.java :
import java.io.*;
public class FormattedInput {
  public int readInt() {
    try {
      for(int i = 0; i < 5; i++) {
        if(tokenizer.nextToken() == tokenizer.TT_NUMBER && tokenizer.nval == (double)((long) tokenizer.nval))
          return (int)tokenizer.nval;
        else {
          System.out.println("Incorrect input: " + tokenizer.sval +
                             " Re-enter an integer");
          continue;
      System.out.println("Five failures reading an int value" + " - program terminated");
      System.exit(1);
      return 0;
    } catch(IOException e) {
      System.out.println(e);
      System.exit(1);
      return 0;
  public String readString() {
    try {
      for(int i = 0; i < 5; i++) {
        int tokenType = tokenizer.nextToken();
        if(tokenType==tokenizer.TT_WORD || tokenType == '\"' || tokenType == '\'') return tokenizer.sval;
        else if(tokenType == '!')
          return "!";
        else {
          System.out.println("Incorrect input. Re-enter a string, please.");
          continue;
      System.out.println("Five failures reading a string" + " - program terminated");
      System.exit(1);
      return null;
    } catch(IOException e) {
      System.out.println(e);
      System.exit(1);
      return null;
  private StreamTokenizer tokenizer = new StreamTokenizer(new InputStreamReader(System.in));
}

Answer 1

Your FormatedInput methods don't throw any InvalidUserInputException
You are also handling the input errors two times once in FormattedInput.java
and in PhoneNumber.java
change it to something like this:
public class FormattedInput {
  public int readInt()
     throws InvalidUserInputException
    try {
        if(tokenizer.nextToken() == tokenizer.TT_NUMBER && tokenizer.nval == (double)((long) tokenizer.nval))
          return (int)tokenizer.nval;
        else {
          // the error handling is done by PhoneNumber which cathes this exception
          throw new InvalidUserInputException("Incorrect input: " + tokenizer.sval +
                             " Re-enter an integer");
    } catch(IOException e) {
      System.out.println(e);
      System.exit(1);
      return 0;
  public String readString()
    throws InvalidUserInputException
    try {
        int tokenType =  tokenizer.nextToken();
        if(tokenType==tokenizer.TT_WORD || tokenType == '\"' || tokenType == '\'') return tokenizer.sval;
        else if(tokenType == '!')
          return "!";
        else {
          // the error handling is done by PhoneNumber which catches this exception
          throw new InvalidUserInputException("Incorrect input. Re-enter a string, please.");
    } catch(IOException e) {
      System.out.println(e);
      System.exit(1);
      return null;
  private StreamTokenizer tokenizer = new StreamTokenizer(new InputStreamReader(System.in));