Retrieve the first object (index [0]) among all objects attached to this page and of a certain class
obj = doc.getObject('XWiki.XWikiComments')
com.xpn.xwiki.api.Object@526252cc

Retrieve all objects attached to this page and of a certain class and one of their properties
XWiki.RicardoRodriguezFernandez
[XWiki.RicardoRodriguezFernandez, XWiki.RicardoRodriguezFernandez, XWiki.RicardoRodriguezFernandez, XWiki.RicardoRodriguezFernandez, XWiki.IsabelListaGarcia, Anonymous, XWiki.YolandaMariaListeMartinez, XWiki.RicardoRodriguezFernandez, XWiki.RicardoRodriguezFernandez]
XWiki.RicardoRodriguezFernandez