public class Account { private Integer balance; public Account(Integer startingBalance) { this.balance = startingBalance; } } public class BankManager { public void openAccount(Customer c) { ... // AVOID: Inefficient primitive constructor accounts.add(new Account(new Integer(0))); // GOOD: Use 'valueOf' accounts.add(new Account(Integer.valueOf(0))); // GOOD: Rely on autoboxing accounts.add(new Account(0)); } }