Contoh ArrayList<Mahasiswa>

import java.util.ArrayList;
import java.util.List;

public class ContohArrayList2 {

    public static void main(String[] args) {
        ArrayList<Mahasiswa> mahasiswa = new ArrayList<>();

        // menambah elemen
        // 1. buat objeknya dulu
        Mahasiswa mhs = new Mahasiswa();
        mhs.setNim("112233");
        mhs.setNama("Adi Putra");

        Mahasiswa mhs2 = new Mahasiswa();
        mhs2.setNim("223344");
        mhs2.setNama("Budi Santoso");

        // 2. memasukkan objek ke arraylist
        mahasiswa.addAll(List.of(mhs, mhs2));

        // mengambil elemen (mhs2)
        Mahasiswa objek = mahasiswa.get(0);
        System.out.println(objek.getNim());
        System.out.println(objek.getNama());

        System.out.println();

        Mahasiswa objek2 = mahasiswa.get(1);
        System.out.println(objek2.getNim());
        System.out.println(objek2.getNama());

        System.out.println("----------");

        for (int i=0; i<mahasiswa.size(); i++) {
            Mahasiswa m = mahasiswa.get(i);
            System.out.println(m.getNim());
        }

        // ubah elemen
        Mahasiswa mhsBaru = new Mahasiswa();
        mhsBaru.setNim("555555");
        mhsBaru.setNama("Cindy");
        mahasiswa.set(1, mhsBaru);

        System.out.println("----------");
        for (int i=0; i<mahasiswa.size(); i++) {
            Mahasiswa m = mahasiswa.get(i);
            System.out.println(m.getNama());
        }

        // hapus elemen
        mahasiswa.remove(1);

        System.out.println("----------");
        for (int i=0; i<mahasiswa.size(); i++) {
            Mahasiswa m = mahasiswa.get(i);
            System.out.println(m.getNama());
        }
    }
}

class Mahasiswa {

    private String nim, nama;

    public String getNim() {
        return nim;
    }

    public void setNim(String nim) {
        this.nim = nim;
    }

    public String getNama() {
        return nama;
    }

    public void setNama(String nama) {
        this.nama = nama;
    }
}