Thread: Having to press 'ENTER' twice

Hello, I am working on a, you could say, a small project where the user is able to create of list of movies they'd like and add, remove, replace it, etc. There are only a limited number of options within the program. The only problem currently that I have is that I have to press the 'ENTER' key twice in order for the program to continue. I've already tried reading up on the difference between the Scanner class's '.next()' and '.nextLine()' and I get that '.next()' reads up until there's a whitespace, while '.nextLine()' reads the whole line, then moving on to the next. I believe my problem to be in my main class, which would be the second code I will paste below.

NOTE: Once again I managed to understand what was wrong after taking a break and giving it some time in my head. The problem was in the main class, and I'll post a third code bit with the solution and pointing at what was the problem.

I have two classes, one for the commands, and a main where everything is executed. Here they are below:

MovieCommands Class

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.ArrayList;
 
public class MovieCommands {
 
	public ArrayList<String> movieList = new ArrayList<String>();
 
	public ArrayList<String> getMovieList(){
		return movieList;
	}
 
	public void addMovieTitle(String movieTitle) {
		if(!(movieList.contains(movieTitle))) {
			movieList.add(movieTitle);
			System.out.println(movieTitle + " was added.");
		}else
			System.out.println(movieTitle + " is already in the list.");
	}
 
	public void printMovieList() {
		if(movieList.size()==0)
			System.out.println("\nThere are no movie titles in this list.");
		else {
			System.out.println("\nMovieList:");
			for(int i=0; i<movieList.size(); i++) {
				System.out.println((i+1) + ". " + movieList.get(i));
			}
		}
	}
 
	private int findMovieTitle(String movieTitle) {
		return movieList.indexOf(movieTitle);
	}
 
	public void searchMovieTitle(String movieTitle) {
		if(findMovieTitle(movieTitle)!=-1)
			System.out.println(movieTitle + " found.");
		else
			System.out.println(movieTitle + " not found.");
	}
 
	public void removeMovieTitle(String movieTitle) {
		if(findMovieTitle(movieTitle)!=-1) {
			movieList.remove(findMovieTitle(movieTitle));
			System.out.println(movieTitle + " was removed.");
		} else
			System.out.println(movieTitle + " does not exist, and thus, was not removed.");
	}
 
	public void replaceMovieTitle(String oldTitle, String newTitle) {
		int index = findMovieTitle(oldTitle);
		if(index != -1) {
			movieList.remove(index);
			movieList.add(index, newTitle);
			System.out.println(oldTitle + " has been replaced with " + newTitle + ".");
		} else
			System.out.println(oldTitle + " does not exist in list.");
	}
 
	public void endProgram() {
		System.out.println("\nShutting down....\nGoodbye.");
		System.exit(0);
	}
 
	public void printOntoFile() {
		try {
			FileWriter fw = new FileWriter("MovieList.txt");
			PrintWriter pw = new PrintWriter(fw, false);
			pw.println("Movie List:");
			for(int i=0; i<movieList.size(); i++) {
				pw.println(movieList.get(i));
			}
			pw.close();
			System.out.println("\nFile created.");
		} catch (IOException e) {
			System.out.println("Oops, something went wrong.");
			e.printStackTrace();
			System.exit(0);
		}
	}
 
	public void readsIntoArrayList() {
		File file = new File("MovieList.txt");
		Scanner input = null;
 
		try {
			input = new Scanner(file);
			input.nextLine();//read in the header and do nothing with it
			while(input.hasNextLine()) {
				movieList.add(input.nextLine());
			}
		} catch (FileNotFoundException e) {
			System.out.println("No file to read from found.\n");
			//e.printStackTrace();		//<--- outputs an error message to console
			//System.exit(0);
		}
 
	}
 
}//end MovieCommands class

Main Class:

import java.util.Scanner;
 
public class MovieMain {
 
	private static Scanner sc = new Scanner(System.in);
	private static MovieCommands movies = new MovieCommands();
 
	public static void main(String[] args) {
 
		movies.readsIntoArrayList();
		System.out.println("Welcome to the movie list application.\nSelect an action from one of the options below:");
		while(true) {
			printOptions();
			System.out.print("Enter your choice: ");
			if(sc.hasNextInt()) {
				int option = sc.nextInt();
				if(option >= 0 && option <=6)
					optionExecution(option);
				else
					System.out.println("\nValue is out of range. Please try again.");
			} else {
				sc.nextLine();
				System.out.println("\nInvalid value. Please try again.");
			}
		}
 
	}//end main
 
	public static void printOptions() {
		System.out.println("\n0 - End program.");
		System.out.println("1 - Add a movie title to the list.");
		System.out.println("2 - Print movie title list.");
		System.out.println("3 - Search for a movie title within the list.");
		System.out.println("4 - Remove a movie title from the list.");
		System.out.println("5 - Replace a movie title within the list.");
		System.out.println("6 - Print the movie list onto a file.");
	}
 
	public static void optionExecution(int optionNum) {
		switch(optionNum) {
		case 0:
			sc.close();
			movies.endProgram();
		case 1:
			System.out.print("\nEnter the movie title you would like to add: ");
			sc.nextLine();
			movies.addMovieTitle(sc.nextLine());
			break;
		case 2:
			movies.printMovieList();
			break;
		case 3:
			System.out.print("\nEnter the movie title you are searching for: ");
			sc.nextLine();
			movies.searchMovieTitle(sc.nextLine());
			break;
		case 4:
			System.out.print("\nEnter the movie title you would like to remove: ");
			sc.nextLine();
			movies.removeMovieTitle(sc.nextLine());
			break;
		case 5:
			System.out.print("\nEnter the movie title you would like to replace: ");
			sc.nextLine();
			String oldTitle = sc.nextLine();
			System.out.print("\nEnter the movie title you would like to replace with: ");
			String newTitle = sc.nextLine();
			movies.replaceMovieTitle(oldTitle, newTitle);
			break;
		case 6:
			movies.printOntoFile();
			System.out.println("Movie list saved onto 'MovieList.txt' file.");
			break;
		}
	}//end optionExecution
 
}//end class

Main Class fixed:

import java.util.Scanner;
 
public class MovieMain {
 
	private static Scanner sc = new Scanner(System.in);
	private static MovieCommands movies = new MovieCommands();
 
	public static void main(String[] args) {
 
		movies.readsIntoArrayList();
		System.out.println("Welcome to the movie list application.");
		while(true) {
			printOptions();
			String optionInput = sc.nextLine();
			boolean hasInt = optionValidation(optionInput);
			if(hasInt) {
				int num = Integer.valueOf(optionInput);
				if(num >= 0 && num <=6)
					optionExecution(num);
				else {
                                        //sc.nextLine()      <--- This bit here was the issue whenever the user woud input an incorrect value, as the scanner would look for another 'ENTER' key/\n due to this
					System.out.println("\n" + "(" + num + ")" + " is not a valid value. Please try again.");
				}
			} else {
                                //sc.nextLine()      <--- This bit here was the issue whenever the user woud input an incorrect value, as the scanner would look for another 'ENTER' key/\n due to this
				System.out.println("\n" + "(" + optionInput + ")" + " is not a valid input. Please try again.");
			}
		}
 
	}//end main
 
	public static void printOptions() {
		System.out.println("\nSelect an action from one of the options below:");
		System.out.println("0 - End program.");
		System.out.println("1 - Add a movie title to the list.");
		System.out.println("2 - Print movie title list.");
		System.out.println("3 - Search for a movie title within the list.");
		System.out.println("4 - Remove a movie title from the list.");
		System.out.println("5 - Replace a movie title within the list.");
		System.out.println("6 - Print the movie list onto a file.");
		System.out.print("Enter your choice:");
	}
 
	public static void optionExecution(int optionNum) {
		switch(optionNum) {
		case 0:
			sc.close();
			movies.endProgram();
		case 1:
			System.out.print("\nEnter the movie title you would like to add: ");
			movies.addMovieTitle(sc.nextLine());
			break;
		case 2:
			movies.printMovieList();
			break;
		case 3:
			System.out.print("\nEnter the movie title you are searching for: ");
			movies.searchMovieTitle(sc.nextLine());
			break;
		case 4:
			System.out.print("\nEnter the movie title you would like to remove: ");
			movies.removeMovieTitle(sc.nextLine());
			break;
		case 5:
			System.out.print("\nEnter the movie title you would like to replace: ");
			String oldTitle = sc.nextLine();
			System.out.print("\nEnter the movie title you would like to replace with: ");
			String newTitle = sc.nextLine();
			movies.replaceMovieTitle(oldTitle, newTitle);
			break;
		case 6:
			movies.printOntoFile();
			System.out.println("Movie list saved onto 'MovieList.txt' file.");
			break;
		}
	}//end optionExecution
 
	public static boolean optionValidation(String input) {
		boolean isAnInt = false;//used to check in the for loop below if the SINGLE String char is at least an int by checking if it may be a num 0-9
		if(input.length()>1 || input.isEmpty()) {
			return false;
		}else {
			for(int i=0; i<10; i++) {
				if(input.equals(String.valueOf(i)))
					isAnInt = true;
			}
			return isAnInt;
		}
	}
 
 
}//end class

It would be helpful for debugging if the value returned by the nextLine method were saved in a variable and printed out so the user could see what the Invalid value was.

I suspect the problem is with the Scanner class and the mixing of the use of the next... and nextLine methods.
It is explained here: https://www.geeksforgeeks.org/why-is...ext-functions/