What is the difference between ResultSet and RowSet in JDBC

A ResultSet maintains a connection to a database and because of that it can’t be serialized and also we cant pass the Resultset object from one class to other class across the network.

RowSet is a disconnected, serializable version of a JDBC ResultSet and also the RowSet extends the ResultSet interface so it has all the methods of ResultSet. The RowSet can be serialized because it doesn’t have a connection to any database and also it can be sent from one class to another across the network.

More on RowSet:

A RowSet can be * connected * or *disconnected* 
A *disconnected* rowset gets a connection to a data source in order to fill itself with data or to propagate changes in data back to the data source, but most of the time it does not have a connection open. While it is disconnected, it does not need a JDBC driver or the full JDBC API, so its footprint is very small. Thus a rowset is an ideal format for sending data over a network to a thin client.  
A connected RowSet is like a wrapper around the ResultSet. 
Implementation: 
A CachedRowSet class—a disconnected rowset that caches its data in memory; not suitable for very large data sets, but an ideal way to provide thin Java clients, such as a Personal Digital Assistant (PDA) or Network Computer (NC), with tabular data  
A JDBCRowSet class—a connected rowset that serves mainly as a thin wrapper around a ResultSet object to make a JDBC driver look like a JavaBeans component  
A WebRowSet class—a connected rowset that uses the HTTP protocol internally to talk to a Java servlet that provides data access; used to make it possible for thin web clients to retrieve and possibly update a set of rows

 

For example when we are querying the database using the ResultSet object, as it is connected to the database until the object is open and it does not contain all the data from your query. Since it has a connection to the database, when you run the next() method if the ResultSet needs more data it can go to the database and get it. The RowSet can not do that since it is not connected to the database so it must load and hold all the data from your query as soon as you run the execute() method. If your query returns a lot or rows you could encounter very slow processing and out of memory errors. However, if the number of rows to be returned is a reasonable number then a RowSet can be used