code: private static String getPackageOfClass(File file) throws IOException {
  		BufferedReader reader = new BufferedReader(new FileReader(file));
  		try {
  			while (true) {
  				String line = reader.readLine();
  				if (line == null) {
  					return null;
  				}
  				if (line.contains("package")) {
  					String[] parts = line.split("[ \t;]");
  					if (parts.length > 1 && parts[0].equals("package")) {
  						return parts[1];
  					}
  				}
  			}
  		} finally {
  			reader.close();
  		}
  	}
docs: Returns the package name of a file that has one of the annotations we are looking for.
  
  @return Package prefix string or null or no annotations.