org.apache.poi.ss.usermodel.Sheet.getCellComments()

[Bazil]

Hi
I'm trying to find comments to cells on a spreadsheet.
All is well, when comments have org.apache.poi.ss.usermodel.Sheet.
getCellComments() returns. But when no comments, an exception is thrown java
.lang.NullPointerException.
Is it possible to do so in this case getCellComments() returned null or an
empty Map?
With respect
Vasily Kopytov