Exception in thread "main" java.lang.NullPointerException

Hi im new to programing and doing forums(this is first forum ive made srry for it not being formated correctly) im currently making a reusable tally class and cant figure out this problem it compiles with no problem but when i run it

Attachment 3247

ive checked online and cant find the awnser as to why its doing this any help would be very appreciated
Here is the code for the Tally program:

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

public class Tally
{
private String title;
private ArrayList<Object> Items;
private ArrayList<Integer> Count;
private int count = 0;


public Tally()
{
title = ("unnamed tally");
Items = new ArrayList<Object>();
Count = new ArrayList<Integer>();
}
public Tally(String name)
{
String title = (name);
Items = new ArrayList<Object>();
Count = new ArrayList<Integer>();
}

public void add(Object item)
{
add(1, item);
}

public void add(int i, Object item)
{
int index = 0;
String counter;
int curCount;

index = Items.indexOf(item);
if(index < 0)
{
Count.add(i);
Items.add(item);
++count;
}
else
{
Items.add(item); // add new object with count of 1
Count.add(i); // updated for v5.0, includes autoboxing
++count;
}
}

public void listAll(PrintStream out)
{

for(int i=0; i<Items.size(); i++)
out.println(Count.get(i)+"\t"+Items.get(i));
}

public void remove(String item)
{
remove(1, item);
}

public void remove(int delCount, Object item)
{
int index = 0;
String counter;
int curCount;
index = Items.indexOf(item);

if(index > 0)
{
curCount = Count.get(index);
curCount -= delCount;
if(curCount>0)
{
Count.set(index, curCount);
}
else
{
purge(index);
}
}

}

public void removeAll(Object item)
{
int index = 0;

index = Items.indexOf(item);
Items.remove(index);
Count.remove(index);
}


public void removeAll()
{
Count.clear();
Items.clear();
}

public int getCount()
{
return count;
}

public String getTitle()
{
return new String(title);
}

public int countOf(Object item)
{

int index = 0;
String counter;
int curCount = 0;

index = Items.indexOf(item);

if(index >= 0) // in list
{
curCount = Count.get(index); // updated for v5.0
}

return curCount;
}

public void purge(int index)
{
//int q = Items.indexOf(item);
Items.remove(index);
Count.remove(index);
--count;
}

}

And here is the code for the TallyTest(This is what we are sposed to use):


/**
* Chapter 09 Solution to programming assignment 7, driver program
*/
public class TallyTest
{
public static void main(String[] argv)
{
tallyChoir();
tallyCoins();
}

private static void tallyChoir()
{
Tally t1 = new Tally("Choir voices");

System.out.println("Creating a new Tally of choir voices.");

t1.add("Soprano"); // only 1 soprano!
t1.add(10,"Alto");
t1.add(12,"Tenor");
t1.add(15,"Bass");

System.out.println("The choir has the following tally of voices:");
t1.listAll(System.out); // lists all to standard output PrintStream

System.out.println("which is, "+t1.getCount()+" different voice parts.\n");

System.out.println("Here is the tally of "+t1.getTitle());
System.out.println(t1.countOf("Soprano")+" sopranos,");
System.out.println(t1.countOf("Alto")+" altos,");
System.out.println(t1.countOf("Tenor")+" tenors, and");
System.out.println(t1.countOf("Bass")+" basses,");

System.out.println("\nFirst, one Bass left.");
t1.remove("Bass");

System.out.println("And then 3 Altos left.");
t1.remove(3, "Alto");

System.out.println("Which left the choir with:");
t1.listAll(System.out);

System.out.println("\nThen all of the Sopranos left.");
t1.removeAll("Soprano");
System.out.println("Which left the choir with:");
t1.listAll(System.out);

System.out.println("\nThen all "+t1.countOf("Tenor")+" of the Tenors left.");
t1.remove(t1.countOf("Tenor"), "Tenor");
System.out.println("Which left the choir with:");
t1.listAll(System.out);

System.out.println("\nThen everyone left.");
t1.removeAll();
System.out.println("Which left:\n");
t1.listAll(System.out);

}

private static void tallyCoins()
{
Tally coinTally = new Tally("Tally of Coins");

System.out.println("Creating a new Tally of coins.");

coinTally.add(12,"Quarters");
coinTally.add(10,"Dimes");
coinTally.add("Nickles");
coinTally.add("Pennies");

System.out.println("This is the tally of coins:");
coinTally.listAll(System.out); // lists all to standard output PrintStream

System.out.println("which is, "+coinTally.getCount()+" different coins.\n");

System.out.println("Here is the "+coinTally.getTitle());
System.out.println(coinTally.countOf("Quarters")+" Quarters,");
System.out.println(coinTally.countOf("Dimes")+" Dimes,");
System.out.println(coinTally.countOf("Nickles")+" Nickles, and");
System.out.println(coinTally.countOf("Pennies")+" Pennies.");

System.out.println("\nFirst, one Penny left.");
coinTally.remove("Pennies");

System.out.println("And then 3 Dimes left.");
coinTally.remove(3, "Dimes");

System.out.println("Which left:");
coinTally.listAll(System.out);

System.out.println("\nThen all of the Quarters left.");
coinTally.removeAll("Quarters");
System.out.println("Which left:");
coinTally.listAll(System.out);

System.out.println("\nThen all of the Nickles left.");
coinTally.remove(7, "Nickles");
System.out.println("Which left:");
coinTally.listAll(System.out);

System.out.println("\nThen everyone left.");
coinTally.removeAll();
System.out.println("Which left:\n");
coinTally.listAll(System.out);
}
}

if anyone will tell me how i will repost the code in the correct way

Please use [code] tags [/code] when posting code as that is unreadable otherwise.
You should also highlight the line that exception occurred on.

Anyway here:

Code:

---

return new String(title);

---

title is null.
But I would ask why you don't simply return title?

Quote:

---

Originally Posted by newProgrammer

Code:

---

        public Tally(String name)
        {
                String title = (name);
                Items = new ArrayList<Object>();
                Count = new ArrayList<Integer>();
        }

---

---

In this constructor you're assigning the name parameter to a local variable (it leaves the member variable 'title' at its null value).

kind regards,

Jos

See?
I couldn't spot that for the lack of code tags.
Still, doesn't answer why they're creating a new String to return.