I am trying to create a case and break statement about if the user is going or not going to a party

User is asked if they are going to the party or not.

final String = YES, Y, NO, N;

    switch (party)
    {
        case yes:
        case YES:
        case Y:
        case y:
            System.out.println(userName + " " + " is attending the party.");
    break;
        case no:
        case NO:
        case N:
        case n:
            System.out.println(userName + " " + " is not attending the party.");
            break;
    default:
        System.out.println("Invalid response.");
    }