Restrict string input from user to alphabetic and numerical values [duplicate]

Answer 1

That is the code

    public class InputLetters {
    String  InputWords;
    Scanner reader;
    boolean [] TF;
    boolean FT;     

    public InputLetters() {

        FT=false;

        while(!FT){     
            System.out.println("Enter that you want to: ");
            reader = new Scanner(System.in);
            InputWords = reader.nextLine();
            Control(InputWords);            
        }

    }


public void Control(String s){
String [] b = s.split(" ");
TF = new boolean[b.length];
    for(int i =0;i