i am having only one field as a primary key in my db table.I am using the class for that , so while deploying in primary key class field i am giving that classname as PRODUCT.ProductPK . In my client code , i am finding by "name" using finder method which works fine . But with findbyprimarykey(ProductPK pk) method which has been defined in home. it gives an exception -- ERROR in database SELECT for find: java.lang.ClassCastException: PRODUCT.ProductPK --- . I am working on J2SDKEE1.2.1 ? So how to tackle this?