public class KotakRaw {
    public static void main(String[] args) {
        KotakObject kotak = new KotakObject();
        kotak.simpan("Budi");
        String nama = (String) kotak.ambil();      // cast eksplisit wajib
        System.out.println("Nama : " + nama);

        kotak.simpan(Integer.valueOf(42));         // kompiler tidak protes
        try {
            String salah = (String) kotak.ambil(); // gagal saat runtime
            System.out.println("Isi  : " + salah);
        } catch (ClassCastException e) {
            System.out.println("Gagal: " + e.getMessage());
        }
    }
}

class KotakObject {
    private Object isi;

    public void simpan(Object nilai) {
        isi = nilai;
    }

    public Object ambil() {
        return isi;
    }
}