Well, you can't, of course. I don't know if you mean "find a file on the disk", in which case the answer is that you really can't, or "find text in some given file," in which case the answer is you can't unless you upload the file to the server. Now, of course, if you're open to doing the work on the client rather than on the server, then you can do either of these in a signed applet. The user would have to grant the file read privilege to the applet, and then it could root around the file system. In any case, this has absolutely nothing to do with "Sockets and Internet Protocols;" we don't have a "Web architecture" forum so I'm going to move this to Applets; followups there.