JDBC를 사용할 때 Java 코드에서 \'결과 세트가 닫힌 후 작업이 허용되지 않음\' 오류가 발생하는 이유는 무엇입니까?

java.sql.SQLException: Operation not allowed after ResultSet closed

<code class="java">ResultSet rs = null;
Connection connection = null;
Statement st = null;
try {
    connection = DriverManager.getConnection("databaseadress","username","password");
    st = connection.createStatement();  
    rs = st.executeQuery(query);
} catch (...) {} // exception handling
finally {
    if (rs != null) rs.close();
    if (st!= null) st.close();
    if (connection != null) connection.close();
}</code>

<code class="java">public static <T> List<T> sqlquery (String query, RowMapper<T> rowMapper) throws SQLException {
    Connection connection = null;
    Statement st = null;
    ResultSet rs = null;
    connection = DriverManager.getConnection("databaseadress","username","password");
    st = connection.createStatement();  
    rs = st.executeQuery(query);
    List<T> list = new ArrayList<>();
    while (rs.next()) {
        list.add(rowMapper.mapRow(rs));
    }
    if (rs != null) rs.close();
    if (st != null) st.close();
    if (connection != null) connection.close();
    return list;
}</code>