Update MoleculeDatabase.java

 */

public class MoleculeDatabase implements Serializable {

    private ArrayList<MoleculeDatabase> db;   // Molecule database

    public ArrayList<MoleculeDatabase> db;   // Molecule database

    /**

     * Private constructor to prevent instantiation from outside

     * Constructs a database

     */

    private MoleculeDatabase() {

    public MoleculeDatabase() {

        this.db = new ArrayList<>();

    }