how am i supposed to store 3 types of data in first ArrayList

[wndtjr2]

I'm coding a bank account program and I've been doing for so long.
I got an instruction from my prof but i don't get it.

here is the instuction.

New data and methods for the CheckingAccount Class

---------------------------------------------------------------------------

private ArrayList<Transaction> transList; // keeps a list of Transaction objects for the account

private int transCount; // the count of Transaction objects and used as the ID for each transaction

public void addTrans( Transaction newTrans) // adds a transaction object to the transList

public int gettransCount() //returns the current value of transCount;

public Transaction getTrans(int i) // returns the i-th Transaction object in the list

--------------------------------------------------------------------------

import java.util.ArrayList;

public class checkingAccount{
      
	private double balance = 0;
	private double totalServiceCharge = 0;	

	public checkingAccount(double initialBalance){

		balance = initialBalance;
	}
	public double getBalance(){
		return balance; 
	}
	public void setBalance(double transAmt, int tCode){
		if(tCode == 1)
			balance -= transAmt;
		else //if(tCode == 2)
			balance += transAmt; 
	}
	public double getServiceCharge(){    
		return totalServiceCharge;
 
	}
	public void setServiceCharge(double currentServiceCharge){
		totalServiceCharge += currentServiceCharge;  
	}
}

New Transaction class

public class Transaction

{

    private int transNumber; 

    private int transId;

    private double transAmt;

    public Transaction(int number, int id, double amount)

    {

        transNumber = number;

        transId = id;

        transAmt = amount;

    }

    public int getTransNumber()

    {

        return transNumber;

    }

    public int getTransId()

    {

        return transId;

    }

    public double getTransAmount()
    {
        return transAmt;
    }
}

[eRaaaa]

And your question is....?

[DiamondSoul]

I'm not entirely sure what you're asking, but if you want to store multiple types of data in an ArrayList, that sounds like polymorphism to me. As a set of different types of bank accounts is a frequently used example for teaching inheritance/polymorphism, I'm guessing you want an ArrayList containing 3 different types of bank accounts that extend a single BankAccount class? If that's the case, you can simply create an object of type ArrayList<BankAccount> and add instances of any of the 3 subclasses to said ArrayList and it will work.

I realize that was rather vague, but so was your question...

[wndtjr2]

I'm sorry the question was so vague.
But what DiamondSoul guessed was I wanted to ask.
Thank you it was helpful for me