Keep on getting one error or the other

[wizar]

I've been either getting NoSuchElementException or NullPointerException errors when working with this code. Right now, I left it so that I have NoSuchElementException errors.

For this program, I am getting a sentence input from the user, and for every word that has "ui" in it, I want to replace it with a 'w'. (instead of "quick", I need to have "qwick" as a result.

Can anyone help me understand this?

import java.io.*;
import java.util.*;

public class LetterChange
{
  public static void main (String [] args) throws IOException
  {
    BufferedReader objReader = new BufferedReader (new InputStreamReader (System.in));
    
    System.out.println ("Enter a sentence to change, enter 'exit' to exit:");
    String input = objReader.readLine();
    String result = "";
    String test= input;
    
    LetterSwitch changed = new LetterSwitch (test, result);// error here
    while (!input.equals("exit"))
    {
      System.out.println(changed.getResult());
      System.out.println ("Enter a sentence to change, enter 'exit' to exit: ");
      input = objReader.readLine();
    }
    if (input.equals("exit"))
    {
      System.out.println("End.");
    } 
  } 
}


class LetterSwitch
{
  private String test;
  private String result= "";
  LetterSwitch(String subject, String differ)
  {
    test = subject;
    result = differ;
    addLetter (test); // error here
  }
  
  public void addLetter (String test)
  {
    StringTokenizer line = new StringTokenizer (test);
    StringBuffer changes = new StringBuffer ();
    
    while (line.hasMoreTokens())
    {
      String word= line.nextToken();
      int x = word.indexOf('u'); 
      if (word.charAt(x + 1) == 'i' )
      {
        word = word.replaceFirst ("ui", "w");
      }
      else 
      {
        word = word;
      }
    }
    changes.append(line.nextToken()); //error on this line
    result = changes.toString();
  }
  String getResult()
  {
    return result;
  }
}

These are the error messages I get:

java.util.NoSuchElementException
at java.util.StringTokenizer.nextToken(Unknown Source)
at LetterSwitch.addLetter(LetterChange.java:59)
at LetterSwitch.<init>(LetterChange.java:38)
at LetterChange.main(LetterChange.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)

[m00nchile]

    while (line.hasMoreTokens())
    {
      String word= line.nextToken();
      int x = word.indexOf('u'); 
      if (word.charAt(x + 1) == 'i' )
      {
        word = word.replaceFirst ("ui", "w");
      }
      else 
      {
        word = word;
      }
    }
    changes.append(line.nextToken()); //error on this line
    result = changes.toString();

While there are more tokens, get next token. When there are no more tokens, get the next token. See what you did there?
EDIT: Also, that else is totaly extraneous, what is word = word supposed to acomplish? What happens if you come across a text like this:
there is nothing for u
Take a look at your method and see what happens when you hit the single letter word "u".

[wizar]

Ok, thanks for pointing that out.
Unless the character after the u is an i, the word should remain the same. I guess it's not necessary?

And that gets a StringIndexOutOfBounds error, should I change the else statement then?

[m00nchile]

Yes, delete the else statement altogether. Also, read up on the indexOf() method, specificaly what it returns if the character was not found in the string. Also, a simple modification to your

if ([B]x < word.length() &&[/B] word.charAt(x + 1) == 'i')

if statement takes care of the string index out of bounds exception as well.

[wizar]

Thanks for your help, I appreciate it. :)
I tried changing the if statement, but I got the index out of bounds error again when I use 'u' as a single character in my input. So I'm a bit confused now.

Here are the error messages I got:
java.lang.StringIndexOutOfBoundsException: String index out of range: 1
at java.lang.String.charAt(Unknown Source)
at LetterSwitch.addLetter(LetterChange.java:50)
at LetterSwitch.<init>(LetterChange.java:38)
at LetterChange.main(LetterChange.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)

EDIT: I fixed my method so I'm not getting this error anymore. Can anyone help me understand why I'm getting the other errors?

[m00nchile]

What errors are you still getting?

[wizar]

The errors I originally had in my first post.
My bad, I should have been more specific.
Thanks again for your help. :)

[wizar]

I am currently working with adding a set method, which seems to eliminate the errors. I'm just having problem with getting an output.

Is adding a set method wrong, or is something wrong with the code without the set method?
Here's the code I have now:

import java.io.*;
import java.util.*;

public class LetterChange
{
  public static void main (String [] args) throws IOException
  {
    BufferedReader objReader = new BufferedReader (new InputStreamReader (System.in));
    
    System.out.println ("Enter a sentence to change, enter 'exit' to exit:");
    String input = objReader.readLine();
    String result = "";
    String test= input;
    String word = "";
    
    StringTokenizer line = new StringTokenizer(test);
    LetterSwitch changed = new LetterSwitch (test, result, word);
    changed.setWord(line.nextToken());
    
    while (!input.equals("exit"))
    {
      System.out.println(changed.getResult());
      System.out.println ("Enter a sentence to change, enter 'exit' to exit: ");
      input = objReader.readLine();
    }
    if (input.equals("exit"))
    {
      System.out.println("End.");
    } 
  } 
}


class LetterSwitch
{
  private String test;
  private String result= "";
  private String word;
  LetterSwitch(String subject, String differ, String term)
  {
    test = subject;
    result = differ;
    word = term;
    addLetter (test, result, word);
  }
  
  String setWord (String term)
  {
    String word = term;
    return word;
  }
  public void addLetter (String test, String result, String word)
  {
    StringTokenizer line = new StringTokenizer (test);
    StringBuffer changes = new StringBuffer ();
    word = line.nextToken();
    while (line.hasMoreTokens())
    {
      int x = word.indexOf('u'); 
      if ((x < word.length()) && (word.charAt(x + 1) == 'i' ))
      {
        word = word.replaceFirst ("ui", "w");
      }
      changes.append(line.nextToken()); 
    }
    
    result = changes.toString();
  }
  String getResult()
  {
    return result;
  }
}