Improve implementation of ResultSet.getMetaData(). The current implementation creates a new ResultSetMetaData each time this method is called which is quite costly if it is called from inside a fetch-loop such as in the example on: https://en.wikipedia.org/wiki/Java_Database_Connectivity#Examples try (Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery("SELECT * FROM MyTable")) { while (rs.next()) { int numColumns = rs.getMetaData().getColumnCount(); for (int i = 1; i <= numColumns; i++) { // Column numbers start at 1. // Also there are many methods on the result set to return // the column as a particular type. Refer to the Sun documentation // for the list of valid conversions. System.out.println( "COLUMN " + i + " = " + rs.getObject(i)); } } } As the ResultSetMetaData is static for a ResultSet it is better to create it once, cache it in the ResultSet object and return the cached object for next calls to ResultSet.getMetaData().