Q:

JDBC and MySQL, how to persist java.util.Date to a DATETIME column?

I'm struggling to understand how to get it to work. I have a prepared statment, and I want to persist a java.util.date. It doesn't work.
I tried to cast it to java.sql.Date, and it still doesn't work.
what's the issue with java date framework, it's really not straight forward.

A:

You should use java.sql.Timestamp to store a java.util.Date in a DATETIME field. If you check the javadocs of both classes (click the above links!), you'll see that the Timestamp has a constructor taking the time in millis and that Date has a getter returning the time in millis. 
Do the math:
preparedStatement.setTimestamp(index, new Timestamp(date.getTime()));
// ...

You should not use java.sql.Date as it represents only the date portion, not the time portion. With this, you would end up with 00:00:00 as time in the DATETIME field.
For your information only, since Timestamp is a subclass of java.util.Date, you could just upcast it whenever you obtain it from the ResultSet.
Date date = resultSet.getTimestamp("columnname");
// ...

