Syntax error on string to int java

im newbie to java , and i getting confused here , why i get error when i want to convert string to int in java , if i type in msi (a to e), and i want to use msii variable inside if statement to outside , and i can't , so i try using sout outside , but i got error , and sorry i have bad grammar

    public static void main(String args[]){
    Scanner i=new Scanner (System.in);
    System.out.println("Name\t\t\t");
    String nama=i.nextLine();
    System.out.println("Nim\t\t\t");
    String nim=i.nextLine();
    System.out.println("grade\t\t");
    String msi=i.next();
    switch(msi) {
        case "a||A":
            {
                msii=Integer.parseInt(msi);
                msii=4;
                break;
            }
        case "b||B":
            {
                 msii=Integer.parseInt(msi);
                msii=3;
                break;
            }
        case "c||C":
            {
                msii=Integer.parseInt(msi);
                msii=2;
                break;
            }
        case "d||D":
            {
                msii=Integer.parseInt(msi);
                msii=1;
                break;
            }
        case "e||E":
            {
                msii=Integer.parseInt(msi);
                msii=4;
                break;
            }
        default:
            System.out.println("tidak ada");
            break;
    }

    System.out.println(+msii);