This week's book giveaway is in the Android forum.
We're giving away four copies of Head First Android and have Dawn & David Griffiths on-line!
See this thread for details.
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes Vector.add() compiler warning Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of Head First Android this week in the Android forum!
JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
Bookmark "Vector.add() compiler warning" Watch "Vector.add() compiler warning" New topic

Vector.add() compiler warning

Meena R. Krishnan
Ranch Hand

Joined: Aug 13, 2006
Posts: 178

I get a compiler warning

What does the second part of the warning mean?
Mike Petrogeorge

Joined: Feb 13, 2007
Posts: 3
Normally, you don't worry about it. However, for the SCJP, or if your doing any generic programming, you need to worry about it.

If you change the declaration to Vector<Integer> v = new Vector<Integer>() your compiler should shut up. I have not looked, but hopefully there is another thread that talks about generics and there you can study the details of that declaration statement.
P Lavti
Ranch Hand

Joined: Mar 27, 2007
Posts: 65
As of Java 5, the <E> syntax is the way that you declare a collection's type. Prior to Java 5 there was no way to specify the type of a collection.
In Java 5, if you are sure that your Vector (or in general your Collection) will contain only one type of objects say String, then you decalre it as:

Vector <String> vec = new Vector <String> ();
[ April 12, 2007: Message edited by: P Lavti ]

-P Lavti<br />SCJP 5.0 (88%)
chandra reddy

Joined: Apr 11, 2007
Posts: 10
Hello Krishna

Vector takes only Objects not primitive types.
Barry Gaunt
Ranch Hand

Joined: Aug 03, 2002
Posts: 7729
Originally posted by chandu:
Hello Krishna

Vector takes only Objects not primitive types.

We are discussing Java 5.0 here where primitive types may be autoboxed into their corresponding wrapper types.
[ April 13, 2007: Message edited by: Barry Gaunt ]

Ask a Meaningful Question and HowToAskQuestionsOnJavaRanch
Getting someone to think and try something out is much more useful than just telling them the answer.
Don't get me started about those stupid light bulbs.
subject: Vector.add() compiler warning
jQuery in Action, 3rd edition