I am writing an application to do some distributed calculations in a peer to peer network. In defining the network I have two class the P2PNetwork and P2PClient. I want these to be generic and so have the definitions of: P2PNetwork<T extends P2PClient<? extends P2PNetwork<T>>> P2PClient<T extends P2PNetwork<? extends T>> with P2PClient defining a method of setNetwork(T network). What I am hoping to describe with this code is: A P2PNetwork is constituted of clients of a certain type A P2PClient may only belong to a network whose clients consist of the same type as this client (the circular-reference) This seems correct to me but if I try to create a non-generic version such as MyP2PClient<MyP2PNetwork<? extends MyP2PClient>> myClient; and other variants I receive numerous errors from the compiler. So my questions are as follows: Is a generic circular reference even possible (I have never seen anything explicitly forbidding it)? Is the above generic definition a correct definition of such a circular relationship? If it is valid, is it the "correct" way to describe such a relationship (i.e. is there another valid definition, which is stylistically preferred)? How would I properly define a non-generic instance of a Client and Server given the proper generic definition?