The EJB container allocates an instance when it receives a request. During the allocation, if the maximum value is specified in the instance pool (the "method-ready" pool of the Stateless Session Bean and the "pool" pool of the Entity Bean), the acquisition of an instance is awaited if another request is being processed in all instances. A timeout can be specified for this waiting time.

If you specify a timeout value, an exception is returned to the client when the instance cannot be acquired within the specified time.

The timeout settings for awaiting instance acquisition are specified as attributes (properties) of the Session Beans or the Entity Beans included in a J2EE application. For details on the settings, see 2.11.6 Defining in cosminexus.xml.