1. you are trying to open output stream for a folder, you did not append fileName to turl.
2. Try creating the directory "\Silicon_new\images" on your root directory and append the fileName to turl and run the app.
You should see the file created properly. (I am sure this is not what you want, but your code trying to do this only).
3. you are trying to use context path as physical file path which is not possible. Read some docs on webapp folder structures and how webapp deployment works. Make sure you read your web-server specific docs, because they are vendor specific.