Changesets and updating work dating bulova movements
An experienced Hibernate developer knows exactly what DDL is going to result from a given mapping configuration.As long as you test and validate that what you expect ends up in the DDL (in dev, qa, staging, etc), you are fine.The easiest way to get started with it would probably be to take your existing DB and then use Liquibase to generate an initial file.
Granted, I don't think there is really a way to "convert datatypes" with without creating a new column, copying the data and blowing away the old column.
We do it in production albeit with an application that's not mission critical and with no highly paid DBAs on staff.
It's just one less manual process that's subject to human error - the application can detect the difference and do the right thing, plus you've presumably tested it in various development and test environments.
However if you did have data in the schema and made a change that resulted in a decrease in column width, you're going to run into either errors or unmanaged data truncation.
Hibernate has to put the disclaimer about not using auto updates in prod to cover themselves when people who don't know what they are doing use it in situations where it should not be used.
That's not a lame answer, and it's not cowboy coding. A person who says "never do it in production" is thinking of a specific set of production deployments, namely the ones he is familiar with (his company, his industry, etc).