Spring boot JPARepository doesn't execute save - spring-boot

Question

Im building a simple app in spring boot and having problems with saving an entity to the db. The bank account is saved normally, but the transaction is not being saved.
The weird thing is that there are no errors or anything. On the first transactionRepository call the method is exited and the app continues normally. I don't get any message in the console or and didn't find any problems using debugging.
Here is the makeTransaction() method, which executes normally until transactionRepository.save(...)
public void makeTransaction(Iban sourceIban, Iban destinationIban, double amount)
throws Exception {
BankAccountEntity sourceAccount = getBankAccountByIban(sourceIban);
BankAccountEntity destinationAccount = getBankAccountByIban(destinationIban);
Date currentDate = new Date();
TransactionEntity sourceTransaction = new TransactionEntity(sourceAccount, sourceIban, destinationIban, currentDate, amount);
TransactionEntity destinationTransaction = new TransactionEntity(destinationAccount, sourceIban, destinationIban, currentDate, amount);
if (sourceAccount.getAmountDeductible() < amount || amount < 0) { // TODO amount checker
throw new Exception(ILLEGAL_TRANSACTION_AMOUNT_TEXT); // TODO change exception type
}
sourceAccount.reduceBalance(amount);
sourceAccount.addTransaction(sourceTransaction);
destinationAccount.increaseBalance(amount);
destinationAccount.addTransaction(destinationTransaction);
bankAccountRepository.save(sourceAccount);
bankAccountRepository.save(destinationAccount);
transactionRepository.save(sourceTransaction);
transactionRepository.saveAndFlush(destinationTransaction);
}
The class has the repositories initialized as follows
private final BankAccountRepository bankAccountRepository;
private final TransactionRepository transactionRepository;
public BankAccountService(#Autowired BankAccountRepository bankAccountRepository,
#Autowired TransactionRepository transactionRepository) {
this.bankAccountRepository = bankAccountRepository;
this.transactionRepository = transactionRepository;
}
The BankAccountRepository looks like this
public interface BankAccountRepository extends JpaRepository<BankAccountEntity, UUID> {
Optional<BankAccountEntity> findByIban(String iban);
}
And the TransactionRepository like this
public interface TransactionRepository extends JpaRepository<TransactionEntity, UUID> {}
The TransactionEntity looks like this
#Entity
#Table(name = "transactions")
public class TransactionEntity {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "transaction_id", nullable = false)
#Type(type = "uuid-char")
private Long transactionId;
private String sourceIban;
private String destinationIban;
private long dateExecuted;
private double amount;
#ManyToOne
#JoinColumn(name = "bank_account_id")
private BankAccountEntity bankAccount;
public TransactionEntity() {
}
public TransactionEntity(BankAccountEntity bankAccount, Iban sourceIban, Iban destinationIban, Date dateExecuted, double amount) {
this.bankAccount = bankAccount;
this.sourceIban = sourceIban.toString();
this.destinationIban = destinationIban.toString();
this.amount = amount;
this.dateExecuted = dateExecuted.getTime();
}
public BankAccountEntity getBankAccount() {
return bankAccount;
}
public void setBankAccount(BankAccountEntity bankAccount) {
this.bankAccount = bankAccount;
}
public Long getTransactionId() {
return transactionId;
}
public void setTransactionId(Long transactionId) {
this.transactionId = transactionId;
}
}