The EJB specification assigns to the EJB container the responsibility for managing threads. Allowing enterprise bean instances to create and manage threads would interfere with the container’s ability to control its components’ lifecycle.

Thread management is not a business function, it is an implementation detail, and is typically complicated and platform-specific. Letting the container manage threads relieves the enterprise bean developer of dealing with threading issues.

Containers deny enterprise beans the privilege to manage threads for three basic reasons: Resource management, security, and thread-sensitive storage.