Czyszczenie bufora klasy Scanner

Zmienna 'choice' nie pozwala na podanie jej wartości z klawiatury gdy wychodzę z "2. Add movie / series to the database\r".

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException; // Signals that an I/O exception of some sort has occurred
import java.io.ObjectOutputStream;
import java.nio.file.Files; // This class consists exclusively of static methods that operate on files, directories, or other types of files
import java.nio.file.Paths; // An object that may be used to locate a file in a file system. It will typically represent a system dependent file path
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner; // A class for reading data from the input

/** The main class of the program */
public class Database {
	
	private static Scanner input = new Scanner(System.in);
	static String choice;
	
	/** Main method */
	static public void main(String[] args) {
		
		createTheRequiredFiles();
		
		while(true) {
			
			System.out.println("1. Browse data" );
			System.out.println("2. Add movie / series to the database\r" );
			System.out.print("\n Your choice: " );
			
			choice = input.nextLine();
			
			switch(choice) {
				case "1": {
					while(true) {
						System.out.println("\n1. Movie database" );
						System.out.println("2. Serials database\r" );
						System.out.print("\n Your choice: " );
						
						choice = input.next();
						
						switch(choice) {
							case "1": {
								//////////////////
								break;
							}
							case "2": {
								//////////////////
								break;
							}
							default: {
								System.err.println("There is no such option in the menu!");
							}
						}
					}
				}
				case "2": {
					while(true) {
						System.out.println("\n1. Add movie..." );
						System.out.println("2. Add series..." );
						System.out.println("9. Back\r" );
						System.out.print("\n Your choice: " );
						
						choice = input.nextLine();
						
						if(choice.equals("9")) {
							break;
						}
						
						switch(choice) {
							case "1": {
								addMovieToTheDatabase();
								
								break;
							}
							case "2": {
								addSeriesToTheDatabase();

								break;
							}
							default: {
								System.out.println("There is no such option in the menu2!");
							}
						}
					}
				}
				default: {
					System.err.println("There is no such option in the menu1!");
				}
			}
		}
	}
	
	/** This method produces the required files */
	static final void createTheRequiredFiles() {
		try {
			Files.createFile(Paths.get("movies.ser"));
			Files.createFile(Paths.get("series.ser"));
		} catch(IOException e) {}
	}
	
	/** This method adds the movie to the database */
	static void addMovieToTheDatabase() {
		
		String title, description, director, releaseDate; 
		int budget; int indexGenre, indexCountry; int rate;
		
		Map<Integer, String> genres = new HashMap<Integer, String>(7);
		genres.put(1, "Comedy");genres.put(2, "Adventure");genres.put(3, "Fantasy");
		genres.put(4, "Animation");genres.put(5, "Horror");genres.put(6, "Thriller");
		genres.put(7, "Action");
		
		Map<Integer, String> country = new HashMap<Integer, String>(3);
		country.put(1, "USA");country.put(2, "UK");country.put(3, "Poland");
		
		System.out.print("\nTitle: ");
		title = input.nextLine();
		System.out.print("Description: ");
		description = input.nextLine();
		System.out.print("Director: ");
		director = input.next();
		System.out.print("Release date DD/MM/YYYY: ");
		releaseDate = input.next();
		System.out.print("Genre: ");
		for(Integer i : genres.keySet()) {
			System.out.print(i + ". " + genres.get(i) + "");
		}
		System.out.print("\nChoice: ");
		indexGenre = input.nextInt();
		System.out.print("Country: ");
		for(Integer i : country.keySet()) {
			System.out.print(i + ". " + country.get(i) + "");
		}
		System.out.print("\nChoice: ");
		indexCountry = input.nextInt();
		System.out.println("Budget: ");
		budget = input.nextInt();
		System.out.println("Rate 1-5: ");
		rate = input.nextInt();
		
		Movie movie = new Movie(title, description, director, releaseDate, genres.get(indexGenre),
				country.get(indexCountry), budget, rate);
		
		if(serialization(movie)) {
			System.out.println("The film has been saved successfully!");
		} else {
			System.out.println("The film was not saved!");
		}
	}
	
	/** This method serializes the object movie. */
	static boolean serialization(Movie movie)
	{
		try {
			ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("movies.ser", true));
			oos.writeObject(movie);
			oos.close();
			
			return true;
		} catch (FileNotFoundException e) {
			System.out.println("Can not find the file. Please try again later...");
			return false;
		} catch (IOException e) {
			System.out.println("Unable to save file. Please try again later...");
			return false;
		}
		
	}
	
	/** This method adds the series to the database */
	static void addSeriesToTheDatabase() {
		
		String title, description, director, releaseDate; 
		int indexGenre, indexCountry; int rate;
		
		Map<Integer, String> genres = new HashMap<Integer, String>(7);
		genres.put(1, "Comedy");genres.put(2, "Adventure");genres.put(3, "Fantasy");
		genres.put(4, "Animation");genres.put(5, "Horror");genres.put(6, "Thriller");
		genres.put(7, "Action");
		
		Map<Integer, String> country = new HashMap<Integer, String>(3);
		country.put(1, "USA");country.put(2, "UK");country.put(3, "Poland");
		
		System.out.print("\nTitle: ");
		title = input.next();
		System.out.print("Description: ");
		description = input.nextLine();
		input.nextLine();
		System.out.print("Director: ");
		director = input.nextLine();
		System.out.print("Release date DD/MM/YYYY: ");
		releaseDate = input.nextLine();
		System.out.print("Genre: ");
		for(Integer i : genres.keySet()) {
			System.out.print(i + ". " + genres.get(i) + "");
		}
		System.out.print("\nChoice: ");
		indexGenre = input.nextInt();
		System.out.print("Country: ");
		for(Integer i : country.keySet()) {
			System.out.print(i + ". " + country.get(i) + "");
		}
		System.out.print("\nChoice: ");
		indexCountry = input.nextInt();
		System.out.println("Rate 1-5: ");
		rate = input.nextInt();
		
		Series series = new Series(title, description, director, releaseDate, genres.get(indexGenre),
				country.get(indexCountry), rate);
		
		if(serialization(series)) {
			System.out.println("The film has been saved successfully!");
		} else {
			System.out.println("The film was not saved!");
		}
	}
	
	/** This method serializes the object series */
	static boolean serialization(Series series)
	{
		try {
			ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("series.ser", true));
			oos.writeObject(series);
			oos.close();
			
			return true;
		} catch (FileNotFoundException e) {
			System.out.println("Can not find the file. Please try again later...");
			return false;
		} catch (IOException e) {
			System.out.println("Unable to save file. Please try again later...");
			return false;
		}
		
	}
}

Tak wynik

1. Browse data
2. Add movie / series to the database


 Your choice: 2

1. Add movie...
2. Add series...
9. Back


 Your choice: 9
1. Browse data
2. Add movie / series to the database


 Your choice: There is no such option in the menu1!

Gdy wracam do głównego menu to wykonuje się automatycznie opcja 'default: '.