How to Resolve IllegalArgumentException: Invalid Column Issue in Java?

What does the IllegalArgumentException: Invalid column error mean in Java and how can it be resolved?

// Java code snippet to connect to database and handle exception
try {
    // Database connection code
  }
catch (IllegalArgumentException e) {
    System.out.println("Error: " + e.getMessage());
}

The IllegalArgumentException: Invalid column error in Java typically arises when attempting to access an invalid or non-existent column in a database query result. This can occur during operations such as ResultSet manipulation in JDBC when the column index or name provided is incorrect or outside the acceptable range.

// Example of accessing a ResultSet column safely
try {
    ResultSet rs = statement.executeQuery("SELECT id, name FROM users");
    while (rs.next()) {
        int id = rs.getInt(1);  // Accessing the first column by index
        String name = rs.getString("name"); // Accessing the column by name
        System.out.println("ID: " + id + ", Name: " + name);
    }
} catch (SQLException e) {
    System.err.println("SQL Exception: " + e.getMessage());
} catch (IllegalArgumentException e) {
    System.err.println("Error: " + e.getMessage());
}

Causes

• An incorrect column index is used when retrieving data from a ResultSet.
• The column name does not match any column in the ResultSet, potentially due to case sensitivity.
• The ResultSet is empty or closed, making column access impossible.

Solutions

• Double-check the index or name of the column you're trying to access. Column indices are 1-based, so ensure you increment appropriately.
• Verify that the SQL query executed correctly and that the expected columns exist in the result set.
• If using column names, ensure they match exactly with the SQL result set’s header, considering case sensitivity.

Mistake: Accessing columns using 0-based index instead of 1-based.

Solution: Always remember that in JDBC, column indexes start from 1.

Mistake: Using column names that don't exactly match the query result (considering case).

Solution: Ensure that string comparisons are case-sensitive; use the exact case as in your SQL query.