Actually our objective is to download the files from the server one by one. To achieve this I am using thread. In the run() method I am connecting to the http server and storing the data in an inputstream. After that I am writing to the file in a while loop 1kb at a time, at the end of the while loop I am changing the updating the progress bar and status of it. This works fine in xp and in windows 7 also but when I remove the LAN wire in xp, status has been changed to ERROR it’s not happening in windows7. All of the above code I wrapped in a try catch block.
The JVM uses the networking DLLs (such as winsock) built into Windows to do all networking; sounds like you've come across a difference between how those DLLs are implemented in XP and 7. You might have to file a bug report with Oracle to get this fixed, they might have to provide special handling on 7. I assume you are using the latest JVM?