Revolut | Sr SWE | Dubai | Aug 2024 | Reject
Role: Senior Software Engineer
Outcome: Rejected
comp offered : 350K-450K AED
Observations:
It was evident that they were specifically looking for a Java expert with experience in payment gateway systems, which I believe should have been clearly mentioned in the job description too.
Interview Process:
-
Initial HR Round:
Discussed the job description and interview process. The HR team was quite helpful and provided an outline of the question scope for each round. -
Coding Round:
Designed a load balancer for 10 servers and wrote corresponding test cases. -
Technical Discussion:
- Implemented a Java method to process a payment transaction from Account A to Account B.
- Converted the same logic into an SQL implementation.
For both rounds, the expectation was to write production-ready code, as if it would be deployed immediately—quite a high bar for an interview scenario.
Outcome:
I received a rejection email from HR with detailed feedback, highlighting my inability to write prod level SQL version of the payment transaction problem.
Payment Transaction [for reference, please validate own your own]:
package revolut;
import java.math.BigDecimal;
public class BankAccount {
private final String accountId;
private BigDecimal balance;
public BankAccount(String accountId, BigDecimal initialBalance) {
this.accountId = accountId;
this.balance = initialBalance;
}
public String getAccountId() {
return accountId;
}
public BigDecimal getBalance() {
return balance;
}
public synchronized void deposit(BigDecimal amount) {
if (amount.compareTo(BigDecimal.ZERO) <= 0) {
throw new IllegalArgumentException("Deposit amount must be greater than zero");
}
balance = balance.add(amount);
System.out.println("Deposited " + amount + " to " + accountId + ", new balance: " + balance);
}
public synchronized void withdraw(BigDecimal amount) {
if (amount.compareTo(BigDecimal.ZERO) <= 0) {
throw new IllegalArgumentException("Withdrawal amount must be greater than zero");
}
if (balance.compareTo(amount) < 0) {
throw new IllegalArgumentException("Insufficient funds in account " + accountId);
}
balance = balance.subtract(amount);
System.out.println("Withdrew " + amount + " from " + accountId + ", new balance: " + balance);
}
public static void transferMoney(BankAccount fromAccount, BankAccount toAccount, BigDecimal amount) {
if (amount.compareTo(BigDecimal.ZERO) <= 0) {
throw new IllegalArgumentException("Transfer amount must be greater than zero");
}
BankAccount firstLock = fromAccount;
BankAccount secondLock = toAccount;
if (fromAccount.getAccountId().compareTo(toAccount.getAccountId()) > 0) {
firstLock = toAccount;
secondLock = fromAccount;
}
synchronized (firstLock) {
synchronized (secondLock) {
fromAccount.withdraw(amount);
toAccount.deposit(amount);
System.out.println("Transferred " + amount + " from " + fromAccount.getAccountId() +
" to " + toAccount.getAccountId());
}
}
}
public static void main(String[] args) {
BankAccount accountA = new BankAccount("A123", new BigDecimal("5000.00"));
BankAccount accountB = new BankAccount("B456", new BigDecimal("3000.00"));
// Create threads to simulate concurrent transfers
Thread t1 = new Thread(() -> transferMoney(accountA, accountB, new BigDecimal("1000.00")));
Thread t2 = new Thread(() -> transferMoney(accountB, accountA, new BigDecimal("500.00")));
t1.start();
t2.start();
try {
t1.join();
t2.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Final balance of Account A: " + accountA.getBalance());
System.out.println("Final balance of Account B: " + accountB.getBalance());
}
}