The RowCallbackHandler is an interface used by the JdbcTemplate class to process result sets. It allows you to process each row of the result set one at a time. The RowCallbackHandler interface contains a single method, processRow, which takes a ResultSet and an int as parameters. The ResultSet contains the data for the current row, while the int represents the row number (starting with 0). You can use the processRow method to access the data in theResultSet and do whatever processing you need to do. For example, you could use it to loop through all the rows in a result set and print out each one. Alternatively, you could use it to insert each row of data into a database table. The RowCallbackHandler is just one of several ways that you can process result sets with Spring. Other options include using a ResultSetExtractor or using aRowMapper. Each of these has its own advantages and disadvantages, so it's important to choose the right one for your particular needs.