I'm writing a simple dictionary program in Java, and I have a problem, so I'm asking you a question.

public class Main Window {
    public static void main(String[] args) {
        int selectMenu = 0;
        String inputWord = null;
        String[] wordArray = new String[20];

        WordPlusMinus wordPlusMinus = new WordPlusMinus();
        WordSearch wordSearch = new WordSearch();
        Scanner scanner = new Scanner(System.in);

        /*
         * Words to be entered: thornbush, crushed, fine hawk, gojuri mijuri, straight autumn, straight autumn, straight autumn, thimble, gombangdae, gomsakda, gomsakda, gomsalgut, gomsalgida, weird, military jongipjeong, gisurak, gilajap, gilaseop, napul, napul, stream, stream
         */

        while(true) {
            System.out.println("==============================================");
            System.out.println ("Pre-program".\t\n");
            System.out.println ("0.Word Type".\n1. Word lookup.\n2.Find the meaning of the word.\n3.Add and clear words.\n4.End Program.");
            System.out.print ("Enter the desired menu number: ");

            selectMenu = scanner.nextInt();
            switch(selectMenu) {
                case 0:
                    for(int i = 0; i < wordArray.length; i++) {
                        System.out.print ("Please enter a word: ");
                        inputWord = scanner.nextLine();
                        wordArray[i] = inputWord;
                    }
                    break;
                case 1:
                    for(int i = 0; i < wordArray.length; i++) {
                        System.out.println(i + "First word: " + wordArray[i]);
                    }
                    break;
                case 2:
    //              //              wordSearch.main(null);
                    break;
                case 3:
    //              //              wordPlusMinus.main(null);
                    break;
                case 4:
                    scanner.close();
                    System.exit(0);
                    break;
            }
        }
    }
}