java - Must JDBC Resultsets and Statements be closed separately although the Connection is closed afterwards?

Question

It is said to be a good habit to close all JDBC resources after usage. But if I have the following code, is it necessary to close the Resultset and the Statement?

Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
    conn = // Retrieve connection
    stmt = conn.prepareStatement(// Some SQL);
    rs = stmt.executeQuery();
} catch(Exception e) {
    // Error Handling
} finally {
    try { if (rs != null) rs.close(); } catch (Exception e) {};
    try { if (stmt != null) stmt.close(); } catch (Exception e) {};
    try { if (conn != null) conn.close(); } catch (Exception e) {};
}

The question is if the closing of the connection does the job or if it leaves some resources in use.

Answer 1

What you have done is perfect and very good practice.

The reason I say its good practice... For example, if for some reason you are using a "primitive" type of database pooling and you call connection.close(), the connection will be returned to the pool and the ResultSet/Statement will never be closed and then you will run into many different new problems!

So you can't always count on connection.close() to clean up.

I hope this helps :)