transfer-transaction-1.java

connection.setAutoCommit(false);
connection.setSavepoint();

try (PreparedStatement selectAccountStatementFrom = connection.prepareStatement(SELECT_ACCOUNT_BY_OWNER_SQL);
     PreparedStatement selectAccountStatementTo = connection.prepareStatement(SELECT_ACCOUNT_BY_OWNER_SQL);
     PreparedStatement updateAccountStatement = connection.prepareStatement(UPDATE_ACCOUNT_SQL)) {

    ResultSet accountFrom = findAccount(bankTransfer.getFrom(), selectAccountStatementFrom);
    ResultSet accountTo = findAccount(bankTransfer.getTo(), selectAccountStatementTo);
    BigDecimal amount = bankTransfer.getAmount();

    if (dataPresent(accountFrom, accountTo)) {
        if (sufficientAccountBalance(amount, accountFrom)) {
            decreaseAccountBalance(updateAccountStatement, accountFrom, amount);
            updateAccountStatement.executeUpdate();
            increaseAccountBalance(updateAccountStatement, accountTo, amount);
            updateAccountStatement.executeUpdate();
        } else {
            throw new BusinessException("Insufficient account balance");
        }
    } else {
        throw new BusinessException("Incorrect account provided");
    }
    connection.commit();
} catch (Exception e) {
    connection.rollback();
    System.out.printf("Error when performing transfer %s \n", e.getMessage());
    throw e;
}