Pause and resume a download

i'm trying to figure out how to pause and resume a download. i'm working on an application that can transfer files between two or more computers and i'm kinda stuck on the pause and resume thing. i'm using a randomaccessfile for reading and writing the file so i can seek to a particular spot in the file and then start reading or writing, so i assume that that'll work for the pause and download for the file. no how do i do it with the socket and the output and input stream? could somebody tell me please. thanks...