import java.sql.Connection;
import java.sql.SQLException;
import java.sql.CallableStatement;

public class Main
{
        private interface MyStatement extends CallableStatement{}

        public void doit( Connection conn )
        {
                CallableStatement stmt = null;
                MyStatement stmt2 = null;
                try
                {
                        stmt = conn.prepareCall( "xxx" );
                        stmt2 = (MyStatement) conn.prepareCall( "xxx" );
                }
                catch ( SQLException e )
                {
                        e.printStackTrace();
                }
                finally
                {
                        if ( stmt != null )
                        {
                                try { stmt.close();     } catch ( SQLException e ) { e.printStackTrace(); }
                        }
                        if ( stmt2 != null )
                        {
                                try { stmt2.close();    } catch ( SQLException e ) { e.printStackTrace(); }
                        }
                }
        }
}