i am having only one field as a primary key in my database table.I am using the class ( --Classname ProductPK in package PRODUCT --)for that .So while deploying in primary key class field i am giving that classname as PRODUCT.ProductPK or should i give "java.lang.Object"? In my client code , i am finding by "name" using finder method findbyName() 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 .