[9] [xxs] RFR 8138938: Clarify javadoc for java.util.Collections.copy()

[Ivan Gerasimov]

Hello!

It was suggested that the javadoc for the java.util.Collections.copy() 
method can be clarified.
Currently it says that the dest list must be long enough, not specifying 
what it means to be long.
The submitter claims that it may be treated that the capacity of the 
list must be large enough, which is not what what was meant.

The fix does not change meaning of the doc, so it should not be 
considered as a spec change.
Would you please help review the javadoc clarification.

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8138938
WEBREV: http://cr.openjdk.java.net/~igerasim/8138938/00/webrev/

Sincerely yours,
Ivan