A DESCRIPTION OF THE PROBLEM :
The page given by the URL contains a couple of instances of the same error.

The word "it's" is used incorrectly in the phrases "it's setComponent method" and "it's relationship". The correct word in these contexts is "its".

The form "it's" is only ever used to indicate contraction of "it is", never as the possessive pronoun "its".

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
"its setComponent method" and "its relationship"
ACTUAL -
"it's setComponent method" and "it's relationship"

URL OF FAULTY DOCUMENTATION :
http://download.java.net/jdk7/docs/api/javax/swing/text/EditorKit.html