a. max-beans-in-free-pool

b. max-beans-in-cache

c. max-beans-in-memory

d. max-stateless-beans-in-cache

Choice A is correct. WebLogic Server maintains a free pool of EJBs for every stateless session bean class. The max-beans-in-free-pool element defines the size of this pool. By default, max-beans-in-free-pool has no limit; the maximum number of beans in the free pool is limited only by the available memory.

When EJBs are created, the session bean instance is created and given an identity. When the client removes a bean, the bean instance is placed in the free pool. When you create a subsequent bean, you can avoid object allocation by reusing the previous instance that is in the free pool. So the max-beans-in-free-pool element can improve performance if EJBs are frequently created and removed. Keeping this parameter too high uses extra memory and keeping it too low causes unnecessary object creation.

WebLogic Server allows you to configure the number of active beans that are present in the EJB cache (the in-memory space where beans exist). The max-beans-in-cache element specifies the maximum number of objects of this class that are allowed in memory. When max-bean-in-cache is reached, WebLogic Server passivates some EJBs that have not been recently used by a client. Choices C and D are not valid properties.