EJB 面试题与答案

Question: Can I develop an Entity Bean without implementing the create() method in the home interface?

Answer: As per the specifications, there can be �ZERO� or �MORE� create() methods defined in an Entity Bean. In cases where create() method is not provided, the only way to access the bean is by knowing its primary key, and by acquiring a handle to it by using its corresponding finder method. In those cases, you can create an instance of a bean based on the data present in the table. All one needs to know is the primary key of that table. i.e. a set a columns that uniquely identify a single row in that table. Once this is known, one can use the �getPrimaryKey()� to get a remote reference to that bean, which can further be used to invoke business methods.