Need inputs on Design pattern

I need pre defined objects obj1, obj2 ..of certain classes Class1, Class2.... These objects reside in a service and lifetime of these objects should be lifeime of service itself. Whenever I call this service to request for a particular object, the service should just pick those objects out of the shelf and provide it to me. Note that, it should not create that object after I request it. It can create for the first time, if it wants to.

What design patten matches my requirement?