Is it possible to save changes to the database immediately after modifying data in the ResultSet without additional operations?

No, changes in the ResultSet are not automatically saved to the database. ResultSet is a representation of data retrieved from the database, and changes within it are stored in memory.

To save changes, you need to use update methods, for example, through Statement or PreparedStatement, or use an updatable ResultSet with a call to the updateRow() method. But even in this case, proper configuration of the ResultSet and calling the appropriate methods are required to commit the changes.

Example of updating a row in ResultSet:

ResultSet rs = stmt.executeQuery("SELECT * FROM users", ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
if(rs.next()) {
    rs.updateString("name", "New Name");
    rs.updateRow(); // changes are saved to the database
}