I have a script that i need help with from school, i have an arraylist and i need to switch that for a HashMap. I would appreciate if anyone can help. THANKS

Code:
 import java.util.*; 
 
/**
*
*/
 
 
public class Bank
{
// Storage for an arbitrary number of AccountAtBank objects
 
private ArrayList<AccountAtBank> bankAccounts;
 
 
// Storage for an
...