Why Do I Get a 'Before Start of Result Set' Exception When Accessing ResultSet Data?

ResultSet Exception: "Before Start of Result Set"

When retrieving data from a ResultSet object, you may encounter an exception with the message "Before start of result set." This error occurs when attempting to access result data before the cursor has been moved to the first row.

To address this issue, ensure that you explicitly move the cursor to the first row using the next() method before trying to retrieve data. The corrected code below demonstrates this correction:

    ResultSet result = prep.executeQuery();
    if (result.next()) { // Move cursor to first row
        String foundType = result.getString(1);

        if (!foundType.equals("meet")) {
            throw new IllegalArgumentException(String.format("Node %d must be of type 'meet', but was %s", meetNID, foundType));
        }
    }

Alternatively, you can use a while loop to iterate through the result set, moving the cursor through each row until there are no more rows to process:

    ResultSet result = prep.executeQuery();
    while (result.next()) {
        String foundType = result.getString(1);

        if (!foundType.equals("meet")) {
            throw new IllegalArgumentException(String.format("Node %d must be of type 'meet', but was %s", meetNID, foundType));
        }
    }

By moving the cursor to the first row (or iterating through the result set using a loop), you can successfully retrieve data and handle exceptions gracefully.

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