POJO used by Hibernate needs to implement hashCode() and equals() method.That's a kind of stuffy work and will be done many many times during development.Some IDEs support automatical generation feature such as IDEA.Eclipse famous plug-in--MyElipse also suppots but it's not free of charge.
I think nearly all JAVAers know Apache Commons open source project.We can use Commons lib to generate hashCode() and equals() method.I wanna tell you that there is also a plugin for Eclipse called Commons4E which help you generate hasCode() and equals().
It also can generate toString() and compareTo() method.That's a smart plugin.Enjoy it.Link