Final answer:
In Java, you can use a protected data field of type ArrayList to store transactions for the accounts.
Step-by-step explanation:
In Java, you can define a protected data field called transactions of type ArrayList to store transactions for the accounts. You will need to import the ArrayList class from the java.util package. Each transaction is an instance of the Transaction class. To define this class, you can create a separate file called Transaction.java and include the necessary attributes and methods. Here's an example:
import java.util.ArrayList;
public class YourClassName {
protected ArrayList<Transaction> transactions;
// Other class members and methods
}
public class Transaction {
// Define attributes and methods for the Transaction class
}