What are the disadvantages of using unmanaged threads in a managed environment?


What are the disadvantages of creating my own threads inside a managed environment like a weblogic application server?
I have always used managed threads (using the WorkManager api) whenever i am working inside an application server.
However I am unclear on the disadvantages or issues that might be caused by using non-managed threads inside the app server.

You just lose the benefits of having managed threads. Managed threads give you the ability to allocate threads from "pools" with maximal and minimal size, an increment rate, and the ability to queue requests for each pool if it is under heavy load. you also have the benefit of being able to monitor these threads and control their behavior in run-time (e.g. from the Weblogic console).