FileUtils from apache commons is a pretty good way to achieve this in a single line.
FileOutputStream s = FileUtils.openOutputStream(new File("/home/nikhil/somedir/file.txt"))
This will create parent folders if do not exist and create a file if not exists and throw a exception if file object is a directory or cannot be written to. This is equivalent to:
File file = new File("/home/nikhil/somedir/file.txt");
file.getParentFile().mkdirs(); // Will create parent directories if not exists
file.createNewFile();
FileOutputStream s = new FileOutputStream(file,false);
All the above operations will throw an exception if the current user is not permitted to do the operation.