Convert letter grade to number

The problem

Write a program that prompts the user to enter a letter grade A, B, C, D, or F and displays its corresponding numeric value 4, 3, 2, 1, or 0.

Breaking it down

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    System.out.print("Enter a letter grade: ");
    String ch = input.next();
    input.close();

    Map<String, Integer> gradeMap = new HashMap<>();
    gradeMap.put("A", 4);
    gradeMap.put("B", 3);
    gradeMap.put("C", 2);
    gradeMap.put("D", 1);
    gradeMap.put("F", 0);

    Integer value = gradeMap.get(ch);

    System.out.println("The numeric value for grade " + ch + " is " + value);

}

Output

Enter a letter grade: A
The numeric value for grade A is 4