Fibonacci with Memoization

FibMain.java

/*
 * Name:  Prof. Antonio C. Silvestri (STCC)
 * Date:  11/05/2019
 * Course Number:  CSC-220
 * Course Name:  Data Structures and Algorithms
 * Problem Number: NAH
 * Email:  silvestri@stcc.edu
 * Description:  Fibonacci Application
 */

import java.util.InputMismatchException;
import java.util.Scanner;

public class FibMain {
	private static final String TITLE = "Fibonacci Application V1.0";
	private static final String CONTINUE_PROMPT = "Do this again? [y/N] ";

	// **********************************************

	private static int getNumber(Scanner sc) {
		do {
			try {
				System.out.print("Enter Number: ");
				return sc.nextInt();
			} catch (InputMismatchException ex) {
				System.out.println("Number must be an integer!");
			} finally {
				sc.nextLine();
			}
		} while (true);
	}
	
	// **********************************************

	private static void process(Scanner sc, String args[]) {
		try {
			int n = getNumber(sc);
			int ans = Fibonacci1.fib(n);
			System.out.println("Ans = " + ans);
			
		} 
		catch (RuntimeException ex) {
			System.out.println("Fibonacci Exception: " + ex.getMessage());
		}
	}

	// **********************************************

	private static boolean doThisAgain(Scanner sc, String prompt) {
		System.out.print(prompt);
		String doOver = sc.nextLine();
		return doOver.equalsIgnoreCase("Y");
	}

	// **********************************************

	public static void main(String args[]) {
		System.out.println("Welcome to " + TITLE);
		Scanner sc = new Scanner(System.in);
		do {
			process(sc, args);
		} while (doThisAgain(sc, CONTINUE_PROMPT));
		sc.close();
		System.out.println("Thank you for using " + TITLE);
	}

}

Fibonacci1.java

import java.util.ArrayList;
import java.util.Collections;

public class Fibonacci1 {
	
	private static int fib(int n, ArrayList<Integer> fibList) {
		if (n == 0)
			return 0;
		if (n == 1)
			return 1;
		if (fibList.get(n) == 0)
			fibList.set(n, fib(n-1, fibList) + fib(n-2, fibList));
		return fibList.get(n);
	}
	
	public static int fib(int n) {
		final int MAX_FIB = 60;
		final ArrayList<Integer> fibList = new ArrayList<>(Collections.nCopies(MAX_FIB, 0));
		if (n > fibList.size())
			throw new RuntimeException("n must be <= 60");
		return fib(n, fibList);		
	}
	
}

Fibonacci2.java

import java.util.ArrayList;
import java.util.Collections;

public class Fibonacci2 {
	private final static ArrayList<Integer> fibList = new ArrayList<Integer>(Collections.nCopies(60, 0));
	
	private static int fibHelper(int n) {
		if (n == 0)
			return 0;
		if (n == 1)
			return 1;
		if (fibList.get(n) == 0)
			fibList.set(n, fibHelper(n-1) + fibHelper(n-2));
		return fibList.get(n);
	}
	
	public static int fib(int n) {
		if (n > fibList.size())
			throw new RuntimeException("n must be <= 60");
		return fibHelper(n);		
	}

}