Retrieves a ResultSetMetaData object that contains information about the columns of the ResultSet object that will be returned when this PreparedStatement object is executed.

Because a PreparedStatement object is precompiled, it is possible to know about the ResultSet object that it will return without having to execute it. Consequently, it is possible to invoke the method getMetaData on a PreparedStatement object rather than waiting to execute it and then invoking the ResultSet.getMetaData method on the ResultSet object that is returned.

NOTE: Using this method may be expensive for some drivers due to the lack of underlying DBMS support.

Returns:  the description of a ResultSet object's columns or null if the driver cannot return a ResultSetMetaData object

Exceptions:

SQLException		if a database access error occurs or this method is called on a closed PreparedStatement
SQLFeatureNotSupportedException		if the JDBC driver does not support this method

Since:  1.2