一些数据库操作可能会导致一个警告而不是由一个例外。这些警告必须明确检查。一个例子警告是一个数据截断误差在读操作（见DataTruncation 类） 。

-Some database operations can cause a warning which is not handled by an exception. These warning must be explicitly checked for. An example of a warning is a data truncation error during a read operation (see the DataTruncation class).

There are three places to check for a warning--- on a Connection object, a Statement object, and a ResultSet object. This example demonstrates how to check for warning on each of these objects.