Create a playlist of songs in Java

InvalidLengthException.java

public class InvalidLengthException extends Exception
{

	private String lengthSent;
	
	//Creates a blank InvalidLengthException with no arguements.
	private InvalidLengthException()
	{
		
	}

	//Creates an InvalidLengthException that takes in the invalid String.
	public InvalidLengthException(String inString)
	{
		this.lengthSent = inString;
	}
	
	//Returns the inString of an InvalidLengthException.
	public String getLengthSet()
	{
		return this.lengthSent;
	}
	
	//Returns InvalidLengthException as a String.
	public String toString()
	{
		String returnString;
		
		returnString = this.lengthSent + " is an invalid length!\n";
		
		return returnString;
	}
	
}

InvalidRatingException.java

public class InvalidRatingException extends Exception
{

	private int numberSent;
	
	//Creates a blank InvalidRatingException with no arguments.
	private InvalidRatingException()
	{
		
	}

	//Creates an InvalidRatingException with the invalid number.
	public InvalidRatingException(int inNumberSent)
	{
		this.numberSent = inNumberSent;
	}
	
	//Returns the numberSent of an InvalidRatingException.
	public int getNumberSent()
	{
		return this.numberSent;
	}
	
	//Returns InvalidRatingException as a String.
	public String toString()
	{
		String returnString;
		
		returnString = this.numberSent + " is an invalid rating! Please choose a rating between 1 and 5.\n";
		
		return returnString;
	}
}

Main.java

public class Main
{
	public static void main( String[] arg)
	{
		Menu menu = new Menu();
		
		menu.loadPlaylist();
		menu.runMenu();

	}
	
} //End class

Menu.java

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

public class Menu
{
	
	private Scanner scan = new Scanner(System.in);
	private Playlist playlist = new Playlist();	
	
	//Display a menu, prompts for user input (int selection), and returns the input.
	public int showMenu()
	{
		int selection;

		System.out.print("\nWhat would you like to do?"
						+ "\n1- Add song"+ "\n2- View playlist"
						+ "\n3- Update song" + "\n4- Remove song" + "\n5- Delete playlist"
						+ " \n6- Exit" + "\nSelection: ");
		selection = scan.nextInt();
		System.out.print("\n");

		return selection;
	}
	
	//Displays menu from showMenu(): Contains a switch,
	//executes case based on returned int from showMenu().
	public void runMenu()
	{

		int selection = showMenu();

		switch (selection) {
		case 1:
			addSong();
			savePlaylist();
			runMenu();
			break;
		case 2:
			viewPlaylist();
			runMenu();
			break;
		case 3:
			updateSong();
			savePlaylist();
			runMenu();
			break;
		case 4:
			removeSong();
			savePlaylist();
			runMenu();
			break;
		case 5:
			playlist.deletePlaylist();
			runMenu();
			break;
		case 6:
			savePlaylist();
			System.exit(0);
			break;
		default:
			System.out.println("\nThat is not a valid selection!\n");
			runMenu();
		}

	}
	
	//Creates a new Song with user to input for artist, title,
	//length, genre, rating; adds Song to a Playlist.
	/* I had a lot of trouble getting the scanner get the input and assign it correctly.
	 * Someone suggested I utilize scanner.reset(), but I'd get a scanner exception. This way worked.*/
	public void addSong()
	{
		Song newSong = new Song(null, null, null, null, 0);
		
		newSong.setArtist(scan.nextLine());
		System.out.print("Enter artist: ");
		newSong.setArtist(scan.nextLine());
		System.out.print("Enter title: ");
		newSong.setTitle(scan.nextLine());
		do
		{
			try
			{
				System.out.print("Enter length: ");
				newSong.setLength(scan.next());
			}
			catch (InvalidLengthException invalidLength)
			{
				System.out.print(invalidLength.toString());
				System.out.print("Enter length as \"minutes:seconds\".\n");
			}
		}while (newSong.getLength() == null);
		
		newSong.setGenre(scan.nextLine());
		System.out.print("Enter genre: ");
		newSong.setGenre(scan.nextLine());
		boolean flag = false;
		do
		{	
			try
			{
				System.out.print("Enter rating: ");
				newSong.setRating(scan.nextInt());
				flag = true;
			}
			catch (InvalidRatingException invalidRating)
			{
				System.out.print(invalidRating.toString());
			}
		} while(flag == false);
		
		playlist.addSong(newSong);
	}
	
	//Formats and displays all Songs in Playlist.
	public void viewPlaylist()
	{
		if(playlist.getPlaylistSize() == 0)
		{
			System.out.println("\nPlaylist empty!");
		}
		else
		{
			for(int i = 0; i < playlist.getPlaylistSize(); i++)
			{
				System.out.print("\n#" + (i+1) + " ");
				System.out.print(""+ playlist.getArtist(i) + " - ");
				System.out.print("\"" +playlist.getTitle(i)+ "\"" + ", ");
				System.out.print(playlist.getLength(i) + ", ");
				System.out.print(playlist.getGenre(i) + ", ");
				System.out.print(playlist.getRating(i)+ " out of 5");
			}
			System.out.print("\n");
		}
	}
	
	//Displays Playlist; prompts user to select song,
	//asks which variable of song they would like to update,
	//asks for input for that variable to update.
	public void updateSong()
	{
		if(playlist.getPlaylistSize() == 0)
		{
			System.out.println("\nPlaylist empty!");
		}
		else
		{
			viewPlaylist();
			System.out.print("\nPlease select a song to update: ");
			int songSelection = scan.nextInt();
			
			System.out.print("\nWhat would you like to update?\n"+"1- Artist\n"+"2- Title\n"
							+"3- Length\n"+"4- Genre\n"+"5- Rating\n"+"Selection: ");
			
			int updateSelection = scan.nextInt();
			
			switch (updateSelection) {
			case 1:
				System.out.print("Enter artist: ");
				String artist = scan.next();
				playlist.updateArtist(songSelection, artist);
				break;
			case 2:
				System.out.print("Enter title: ");
				String title = scan.next();
				playlist.updateTitle(songSelection, title);
				break;
			case 3:
				boolean lengthFlag = false;
				do
				{
					try
					{
						System.out.print("Enter Length: ");
						String length = scan.next();
						playlist.updateLength(songSelection, length);
						lengthFlag = true;
					}
					catch (InvalidLengthException invalidLength)
					{
						System.out.print(invalidLength.toString());
						System.out.print("Enter length as \"minutes:seconds\".\n");
					}
				}while (lengthFlag == false);
				break;
			case 4:
				System.out.print("Enter genre: ");
				String genre = scan.next();
				playlist.updateGenre(songSelection, genre);
				break;
			case 5:
				boolean ratingFlag = false;
				do
				{
					try
					{
						System.out.print("Enter rating: ");
						int rating = scan.nextInt();
						playlist.updateRating(songSelection, rating);
						ratingFlag = true;
					}
					catch (InvalidRatingException invalidLength)
					{
						System.out.print(invalidLength.toString());
					}
				}while (ratingFlag == false);
				break;
			default:
				System.out.println("\nThat is not a valid selection!\n");
				runMenu();
			}
		}
	}
	
	//Displays Playlist; prompts user to select Song to delete and removes it from Playlist.
	public void removeSong()
	{
		if(playlist.getPlaylistSize() == 0)
		{
			System.out.println("\nPlaylist is empty!");
		}
		else
		{
			viewPlaylist();
			boolean flag = false;
			do
			{
				System.out.print("\nSelect a song to remove: ");
				int removeSelection = scan.nextInt();
				
				if(removeSelection < playlist.getPlaylistSize() || removeSelection > playlist.getPlaylistSize())
				{
					System.out.print("That is not a valid selection!\n");
				}
				else
				{
					playlist.removeSong(--removeSelection);
					flag = true;
				}
			} while(flag == false);
		}
	}
	
	//Write the contents of Playlist to a file called playlist.
	public void savePlaylist()
	{
		try
		{
			FileOutputStream fileOutputStream = new FileOutputStream("playlist");
			
			ObjectOutputStream outObjectStream = new ObjectOutputStream(fileOutputStream);
			
			outObjectStream.writeObject(playlist);
			
			outObjectStream.flush();
			outObjectStream.close();
		}
		catch(FileNotFoundException fnfException)
		{
			System.out.println("No file");
		}
		catch(IOException ioException)
		{	
			System.out.println("bad IO");
		}

	}
	
	//Reads the file contents containing to a Playlist.
	public void loadPlaylist()
	{
		try
		{
			FileInputStream fileInputStream = new FileInputStream("playlist");
			
			ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
				
			playlist = (Playlist)objectInputStream.readObject();
				
			objectInputStream.close();
		}
		catch(FileNotFoundException fnfException)
		{
			System.out.println("No File");
		}
		catch(IOException ioException)
		{	
			System.out.println("IO no good");
		}
			
		catch(ClassNotFoundException cnfException)
		{	
			System.out.println("This is not a Playlist.");
		}
		
	}
	
	
}//End class

Playlist.java

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

public class Playlist implements Serializable
{
	private ArrayList<Song> playlist;
	
	//Creates a Playlist object that contains an ArrayList for Songs.
	public Playlist()
	{
		playlist = new ArrayList<Song>();
	}
	
	//Adds a Song to a Playlist.
	public void addSong(Song song)
	{
		playlist.add(song);
	}
	
	//Returns the size of a Playlist.
	public int getPlaylistSize()
	{
		return playlist.size();
	}
	
	//Returns the artist of the Song at position (index) of a Playlist.
	public String getArtist(int index)
	{
		return playlist.get(index).getArtist();
	}
	
	//Returns the title of the Song at position (index) of a Playlist.
	public String getTitle(int index)
	{
		return playlist.get(index).getTitle();
	}
	
	//Returns the length of the Song at position (index) of a Playlist.
	public String getLength(int index)
	{
		return playlist.get(index).getLength();
	}
	
	//Returns the genre of the Song at position (index) of a Playlist.
	public String getGenre(int index)
	{
		return playlist.get(index).getGenre();
	}
	
	//Returns the rating of the Song at position (index) of a Playlist.
	public int getRating(int index)
	{
		return playlist.get(index).getRating();
	}
	
	//Sets the artist of the Song at position (index) to artist.
	public void updateArtist(int index, String artist)
	{
		playlist.get(--index).setArtist(artist);
	}
	
	//Sets the title of the Song at position (index) to the title.
	public void updateTitle(int index, String title)
	{
		playlist.get(--index).setTitle(title);
	}
	
	//Sets the length of the Song at position (index) to length; throws InvalidLengthException.
	public void updateLength(int index, String length) throws InvalidLengthException
	{
		if(length.matches("(\\d.*):(\\d.*)"))
		{
			playlist.get(--index).setLength(length);
		}
		else
		{
			throw new InvalidLengthException(length);
		}
	}
	
	//Sets the genre of the Song at position (index) to genre.
	public void updateGenre(int index, String genre)
	{
		playlist.get(--index).setGenre(genre);
	}
	
	//Sets the rating of the Song at position (index) to rating.
	public void updateRating(int index, int rating) throws InvalidRatingException
	{
		if(rating > 0 && rating < 6)
		{
			playlist.get(--index).setRating(rating);
		}
		else
		{
			throw new InvalidRatingException(rating);
		}
	}
	
	//Removes the song located at the specified index from the Playlist.
	public void removeSong(int index)
	{
			playlist.remove(index);
	}
	
	//Clears the Playlist of all Songs by invoking clear() on a Playlist.
	public void deletePlaylist()
	{
		if(playlist.size() == 0)
		{
			System.out.print("Playlist is empty!\n");
		}
		else
		{
			playlist.clear();
			System.out.print("Playlist has been deleted.\n");
		}
	}
	
} //End class

Song.java

import java.io.*;

public class Song implements Serializable
{
	private String artist;
	private String title;
	private String length;
	private String genre;
	private int rating;
	
	//Creates a playlist object with an artist, title, length, genre, and rating.
	public Song(String artist, String title, String length, String genre, int rating)
	{
		this.artist = artist;
		this.title = title;
		this.length = length;
		this.genre = genre;
		this.rating = rating;
	}
	
	//Sets Song's artist to argument artist.
	public void setArtist(String artist)
	{
		this.artist = artist;
	}
	
	//Return the value of artist in a Song.
	public String getArtist()
	{
		return artist;
	}
	
	//Sets Song's title to argument title.
	public void setTitle(String title)
	{
		this.title = title;
	}
	
	//Returns the value of title in a Song.
	public String getTitle()
	{
		return this.title;
	}
	
	//Sets song's length to length argument; creates InvalidLengthException.
	/* This is not exactly how I wanted to do this, instead
	 * this checks for validity by seeing if the argument String
	 * contains both a colon and only numbers.*/
	public void setLength(String length) throws InvalidLengthException
	{
		if(length.matches("(\\d.*):(\\d.*)"))
		{
			this.length = length;
		}
		else
		{
			throw new InvalidLengthException(length);
		}
	}
	
	//Returns the value of length in a Song.
	public String getLength()
	{
		return this.length;

	}
	
	//Sets Song's genre to argument genre.
	public void setGenre(String genre)
	{
		this.genre = genre;
	}
	
	//Returns value of genre in a Song.
	public String getGenre()
	{
		return this.genre;
	}
	
	//Sets Song's rating to argument rating; creates InvalidRatingException.
	public void setRating(int rating) throws InvalidRatingException
	{
		if(rating > 0 || rating < 6)
		{
			this.rating = rating;		}
		else
		{
			throw new InvalidRatingException(rating);
		}
			
	}
	
	//Returns rating value in a Song.
	public int getRating()
	{
		return this.rating;
	}
	
	
} //End class

Does this work?? Plz tell me