sample.java

/**
 * Generic implementation of getting item from DB
 *
 * @param query          SQL query
 * @param mapper         mapper that map {@link ResultSet} T object
 * @param queryArguments callback for filling query arguments
 * @param <T>            POJO
 * @return parsed instance of T
 * @throws SQLException classic sql exception
 * @throws IOException  in case of uploading file
 */
public static <T> T getItem(
        String query, Mapper<T> mapper,
        QueryArguments queryArguments) throws SQLException, IOException {
    T item = null;

    try (Connection conn = ConnectionHelper.getConnection();
         PreparedStatement statement = conn.prepareStatement(query)) {

        conn.setAutoCommit(false);

        // Put query arguments inside
        if (queryArguments != null) {
            queryArguments.put(statement);
        }

        try (OracleResultSet resultSet = (OracleResultSet) statement.executeQuery()) {
            if (resultSet.next()) {
                item = mapper.map(resultSet);
            }
        }

        conn.commit();
    }

    return item;
}

// --------------------------------------

// Pooled connection je PooledConnection
@Nullable
public static Connection getConnection() throws SQLException {
    return sPooledConnection.getConnection();
}