Java String Methods Demo dengan menu

package javastringmethods_hendri;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class JavaStringMethods_Hendri {
    static BufferedReader rd = new BufferedReader(new InputStreamReader(System.in));
    static Scanner sc = new Scanner(System.in);

    public static void tampil_menu() {
        int pil = 0;
        System.out.println("\n=============================================");
        System.out.println("Aplikasi Contoh Operasi dengan String Methods");
        System.out.println("=============================================\n");
        System.out.println("1. Demo charAt()");
        System.out.println("2. Demo concat()");
        System.out.println("3. Demo substring()");
        System.out.println("...");
        System.out.println("9. Keluar Aplikasi");
        System.out.print("Pilih Menu (1-9): ");
        try {
            pil = Integer.valueOf(rd.readLine());
        } catch (Exception e) {
            System.out.println("Kesalahan input !");
        }
        switch (pil) {
            case 1: demo_charAt(); break;
            case 2: demo_concat(); break;
            case 3: demo_substring(); break;
            case 9: System.exit(0);
            default: System.err.println("Pilihan tidak tersedia !");
        }
    }

    public static void main(String[] args) {
        while (true) {
            tampil_menu();
        }
    }

    private static void demo_charAt() {
        String str;
        int index;
        try {
            System.out.print("Masukkan teks: ");
            str = sc.nextLine();
            System.out.print("Ketikkan index yang diinginkan: ");
            index = sc.nextInt();
            System.out.println("Index ke-"+index+" adalah "+str.charAt(index));
        } catch (Exception e) {
            System.out.println("Terjadi Exception: "+ e.getMessage());
        }
    }

    private static void demo_concat() {
        String str1,str2;
        try {
            System.out.print("Masukkan teks 1: ");
            str1 = sc.nextLine();
            System.out.print("Masukkan teks 2: ");
            str2 = sc.nextLine();
            System.out.println("Hasil concat teks 1 dan teks 2: "+str1.concat(str2));
        } catch (Exception e) {
            System.out.println("Terjadi Exception: "+ e.getMessage());
        }
    }

    private static void demo_substring() {
        System.out.println("Belum diimplementasikan.");
    }
}