I'm not being able to understand the concept of pluggable adapter completely. The adapter pattern seems to be pretty straight-forward in the sense that the the adapter adapts the adaptee interface to the target's by object/class adaptation, whatever the approach may be. When we talk about pluggable adapters, does this mean that the adaptee has built-in interface adaptation so as to adjust to the target's interface? I guess i need to do more learning other than GoF book. I'm not being able to decipher the concept given in there. Can someone validate the above understanding of pluggable adapters and if it is true, how it is implemented. The example given in the GoF book is not clear to me. Thanks.