the best way to generate the primary key for entity bean

[zb cong]

hello
i am the beginner to entity bean,and usually use the toplink as the o-r mapping tool.it can generate the unique primary key automatically for me,i don't need to worry about it.
now i transfer to entity bean,i found that i must generate the pk in my code(if i use the integer id as primary key),then invoke the "create" method to insert a record to database,but how can i keep the id unique?
who can introduce me the best mechanism to generate pk for the entity bean?
thank you very much!

[Lasse Koskela]

http://www.theserverside.com//patterns/thread.jsp?thread_id=4228
http://www-106.ibm.com/developerworks/java/library/j-ejbdesign.html

[Andres Gonzalez]

Have a look at EJB design patterns, by floyd marinescu.
You can find a free PDF copy of the book at www.theserverside.com. It's got different patterns on how to generate keys.