Although almost no JDBC application can be written without database metadata methods, compared to other JDBC methods, database metadata methods are slow. When we use a metadata method, a SELECT statement makes two round-trips to the database: one for metadata, and the second for the data. This is very performance expensive. We can improve the performance by minimizing the use of metadata methods.
An application should cache all metadata, as they will not change, so multiple executions are not needed.