Values are assigning null

[Miryanda Johnson]

Hello! I'm hoping someone can help me demystify why the values are returning null. I know this has to be rather obvious but I'm not seeing it. Any help is appreciated.

I believe the issue is occuring under the addContact() method when the values are being assigned. I'm using an ArrayList to send all the information to the constructor, but whatever I'm doing is either overrode or returning a null value.

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

public class BusinessContactRecord implements Serializable
{
	static String firstName,
						lastName,
						phoneNumber,
						email,
						company;
	static Scanner keyBoard = new Scanner(System.in);
	static ArrayList<BusinessContactRecord> contact = new ArrayList<BusinessContactRecord>();

	public BusinessContactRecord()
	{
	}
	
	public BusinessContactRecord(String firstName, String lastName, String phoneNumeber, String email, String company)
	{
		firstName = this.firstName;
		lastName = this.lastName;
		phoneNumber = this.phoneNumber;
		email = this.email;
		company = this.company;
	}
	
	public String getEmail()
	{
		return email;
	}
	
	public void addContact()
	{
		System.out.print("Enter First Name: ");
		String firstName = keyBoard.next();
		
		System.out.print("Enter Last Name: ");
		String lName = keyBoard.next();
		
		System.out.print("Enter Phone Number: ");
		String number = keyBoard.next();
		
		System.out.print("Enter Email Address: ");
		String emailAddy = keyBoard.next();
		
		/*for (int i=0; i<contact.size(); i++)
		{
			BusinessContactRecord c = contact.get(i);
			
			while(c.getEmail() == email)
			{
				System.out.println("Email address already exists");
				System.out.print("Enter Email Address: ");
				email = keyBoard.next();
			}
		}*/
		
		System.out.print("Enter Company Name: ");
		String comp = keyBoard.next();
		
		contact.add(new BusinessContactRecord(firstName, lName, number, emailAddy, comp));
		//load(contact);
		//read();
	}


	public static void load(ArrayList<BusinessContactRecord> contact)
	{
		try
		{
			FileOutputStream fos = new FileOutputStream("contacts.ser");
	   	ObjectOutputStream oos = new ObjectOutputStream(fos);
	  		oos.writeObject(contact);
		}
		catch (FileNotFoundException e)
		{
	   	e.printStackTrace(); 
	   }
		catch (IOException e)
		{
	   	e.printStackTrace();
	   }
	}
	
	public static void read()
	{
		try
		{
	      FileInputStream fis = new FileInputStream("contacts.ser");
	      ObjectInputStream ois = new ObjectInputStream(fis);
	      Object obj = ois.readObject();
	      ArrayList<BusinessContactRecord> listFromFile = (ArrayList) obj;
	      
			for (BusinessContactRecord record: listFromFile)
			{
                System.out.println(record.toString());
         }
 
     	}
		catch (FileNotFoundException e)
		{
      	e.printStackTrace(); 
      }
		catch (IOException e)
		{
         e.printStackTrace();
      }
		catch (ClassNotFoundException e)
		{
         e.printStackTrace();
      }
	}

	public String toString()
	{
		return String.format("%15s %15s %15s %15s %15s", firstName, lastName, phoneNumber, email, company);
	}
	
	public void findContact()
	{
		if(contact.isEmpty())
		{
				System.out.println("No Email Address Found");
		}
		else
		{
			System.out.print("Enter Email Address: "); 
			String email = keyBoard.next();
			
			for(int i=0; i<contact.size(); i++)
			{
				BusinessContactRecord c = contact.get(i);
				
				if(c.getEmail().equals(email))
				{
					System.out.println("\nContact Found: ");
					System.out.println(c);	
				}
				else
				{
					System.out.println("\nNo Email Address Found!");
				}
			}
		}
	}
	
	public void deleteContact()
	{
		if(contact.isEmpty())
		{
			System.out.println("No Students Available");
		}
		else
		{
			System.out.print("Enter Email Address: "); 
			String email = keyBoard.next();
			
			for(int i=0; i<contact.size(); i++)
			{
				BusinessContactRecord c = contact.get(i);
				
				if(c.getEmail().equals(email))
				{
					System.out.println("\nStudent Deleted!");
					contact.remove(i);;	
				}
				else
				{
					System.out.println("\nInvalid Student ID\nNo Student Deleted!");
				}
			}
		}
	}
	
	public void displayContacts()
	{
		//read();
		if(contact.isEmpty()) //checks array to see if empty or not
		{
			System.out.println("No Students Available");
		}
		else
		{	//displays all students
			/*for(Student s: studentList)
			{
				System.out.println(s);
			}*/
			
			for (BusinessContactRecord record: contact)
			{
                System.out.println(record);
         }
		}
	}

}

public class BusinessContactApp
{
	public static void main (String[] args)
	{
		BusinessContactRecord contact = new BusinessContactRecord();
		
		contact.addContact();
		//contact.addContact();
		//contact.findContact();
		//contact.deleteContact();
		contact.displayContacts();
	}
}

[Randall Twede]

i'm in no condition to figure this out right now, but i just wanted to say. null pointer exceptions always seem obvious after you have solved them, but before that they can drive you crazy.

[Miryanda Johnson]

I was able to get the values to stop assigning null values to the variables, by chagning the constructor:

public BusinessContactRecord(String firstName, String lastName, String phoneNumber, String email, String company)
	{
		/*firstName = this. firstName;
		lastName = this.lastName;
		phoneNumber = this.phoneNumber;
		email = this.email;
		company = this.company;*/
		this.firstName = firstName;
		this.lastName = lastName;
		this.phoneNumber = phoneNumber;
		this.email = email;
		this.company = company;
	}

However, whenever calling addContact() twice, the values are being overridden.

Enter First Name: Miranda
Enter Last Name: Miranda
Enter Phone Number: Miranda
Enter Email Address: Miranda
Enter Company Name: Mirnada
Enter First Name: Miles
Enter Last Name: Miles
Enter Phone Number: Miles
Enter Email Address: Miles
Enter Company Name: Miles
          Miles           Miles           Miles           Miles           Miles
          Miles           Miles           Miles           Miles           Miles

I want it so row one is all displaying whatever is entered, then row two displays whatever was entered the second time.

Any help?

[Randall Twede]

good job fixing the constructor i didn't notice you were doing it backwards(wrong). someone else will have to help with the other problem. i don't know the Scanner class and as i implied i am kind of drunk.

[Miryanda Johnson]

All my variables were declared as static. That was causing the overriding I was seeing

[Randall Twede]

good job Miryanda! static variables are the exception not the norm. most of the time you want an instance variable.

[Randall Twede]

and welcome to the ranch. and don't worry if you question seems obvious or stupid. you should see some of the questions i have asked here.

[Campbell Ritchie]

Lots of books show you static fields throughout, but that is not usually good practice.