[Solved] Java Contact Book - Ability to save and Load

[Jason C]

Jason C Asks: Java Contact Book - Ability to save and Load
I am working on a project which allows a user to add a new contact, update an existing contact, remove a contact, list all contacts, save contacts and load contacts. The program I have created works for adding, listing, updating and removing. When implementing the save and l0oad classes I need to catch an IOExceptions and present to the user. Currently the code I have written is erroring for:

exception IOException is never thrown in body of corresponding try statement

This error is presented in the ContactBook class for the save method.

Another error is:

incompatible types: Contact[] cannot be converted to Collection<? extends Contact>

Presented in the ContactBook class load method.

How do I refactor this code to remove these error and allow the program to compile?

Contact

import java.io.Serializable;


public class Contact implements Serializable {


private String name;
private String address;
private String phone;
private String email;

public Contact(String name, String address, String phone, String email) {
    this.name = name;
    this.address = address;
    this.phone = phone;
    this.email = email;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getAddress() {
    return address;
}

public void setAddress(String address) {
    this.address = address;
}

public String getPhone() {
    return phone;
}

public void setPhone(String phone) {
    this.phone = phone;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

@Override
public String toString() {
    String s = new String().format("%-20s%-20s%-20s%-20s\n",name,address,phone,email);
    return s;
}}

ContactBook

import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;



public class ContactBook {

private final ArrayList<Contact> entries;
private final ContactFileManager fileMan;

public ContactBook() {
    entries = new ArrayList<>();
    fileMan = new ContactFileManager();
}

public void add(Contact contact) {
    entries.add(contact);
}

public void update(int index, Contact contact) {
    entries.set(index, contact);
}

public void remove(int index) {
    entries.remove(index);
}

public void save(String filename, Scanner sc) {
    try {
        fileMan.writeContacts(filename, entries);
    } catch (IOException e) {
        System.out.println("Unable to save: " + e.getMessage());
    }
}

public void load (String filename, Scanner sc) {
    try {
        entries.clear();
        entries.addAll(fileMan.readContacts(filename));
    } catch (IOException | ClassNotFoundException e) {
        System.out.println("Unable to load: " + e.getMessage());
    }
}

@Override
public String toString() {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < entries.size(); i++) {
        sb.append(i + 1).append(".\t").append(entries.get(i).toString()).append("\n");
    }
    return sb.toString();
}}

ContactFileManager

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;



public class ContactFileManager {
public static void writeContacts(String fileName, Contact[] contacts) throws IOException 
{
    FileOutputStream fos = new FileOutputStream(fileName);
    ObjectOutputStream oos = new ObjectOutputStream(fos);

    oos.writeObject(contacts);
    oos.close();
    fos.close();
}

public static Contact[] readContacts(String fileName) throws IOException, 
ClassNotFoundException {
    FileInputStream fis = new FileInputStream(fileName);
    ObjectInputStream ois = new ObjectInputStream(fis);

    Contact[] contacts = (Contact[]) ois.readObject();
    ois.close();
    fis.close();

    return contacts;
}}

ContactApp

import java.util.Scanner;

public class ContactApp {
public static void main(String[] args) {
    
    //Declaing variables
    int choice;
    String name, address, phone, email;
    
    Scanner sc = new Scanner(System.in);
    
    ContactBook book = new ContactBook();
    
    choice = 0;
    while (choice != 5) {
        System.out.println("1. List all Contacts");
        System.out.println("2. Add a new Contact");
        System.out.println("3. Update an existing Contact");
        System.out.println("4. Remove a Contact");
        System.out.println("5. Save Contact Book");
        System.out.println("6. Load Contact Book");
        System.out.println("7. Quit");
        System.out.print("Enter your choice: ");
        
        choice = sc.nextInt();
        
        switch (choice) {
            case 1: {
                System.out.println(book.toString());
                continue;
            }
            
            case 2: {
               sc.nextLine();
               System.out.print("Enter a name: ");
               name = sc.nextLine();
               
               System.out.print("Enter an address :");
               address = sc.nextLine();
               
               System.out.print("Enter a phone number :");
               phone = sc.nextLine();
               
               System.out.print("Enter an email address :");
               email = sc.nextLine();
               
               book.add(new Contact(name, address, phone, email));
               
               continue;
            }
            
            case 3: {
                System.out.println(book.toString());                    
                
                System.out.print("Enter index of Contact to update: ");
                int index = sc.nextInt();
                
                sc.nextLine();
                
                System.out.print("Enter a new name: ");
                name = sc.nextLine();
                
                System.out.print("Enter a new address :");
                address = sc.nextLine();
                                   
                System.out.print("Enter a new phone number :");
                phone = sc.nextLine();
               
                System.out.print("Enter a new email address :");
                email = sc.nextLine();
                
                book.update(index - 1, new Contact(name, address, phone, email));
                
                continue;
            }
            
            case 4: {
                System.out.println(book.toString());
                
                System.out.print("Enter position number to delete: ");
                int index = sc.nextInt();
                book.remove(index - 1);
                continue;
            }
            
            case 5: {
                System.out.print("Enter the filename to save: ");
                String filename = sc.nextLine();
                book.save(filename, sc);
                continue;
            }
            
            case 6: {
                System.out.print("Enter the filename to load: ");
                String filename = sc.nextLine();
                book.load(filename, sc);
                continue;
            }
            
            case 7: {
                continue;
            }
            
            default: {
                System.out.println("** Invalid Choice.  Please try again.");
            }
        }
        sc.close();
    }
}}