LongBlob means you can store any binary data in there. That includes serialized objects; you could get an OutputStream from the PreparedStatement, wrap that in an ObjectOutputStream, than write the ArrayList to that. Don't forget to close the ObjectOutputStream or the serialization footer won't be present.
One major drawback with this approach: if the class changes and you haven't prepared for that properly (e.g. with a fixed serialVersionUid field) you will get an exception when getting the data back from the database.