script: https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/utilities/add_snippets_to_file.py

1. Method signature with @nullable does not work.
   Fix:
   At this line in add_snippets_to_file.py#L99, replace the existing:
   ',\s+'.join(['(final\s+)?{}\s+{}'.format(
   with this:
   ',\s+'.join(['(@nullable\s+)?(final\s+)?{}\s+{}'.format(

2. for all single line comments, the script either fails (when its the last method in the file) or appends javadocs to the successive method.

example:
/** some javadoc */
public String method ( String args );