Vector.add() compiler warning

[Meena R. Krishnan]

Vector v = new Vector();
v.add(40);

I get a compiler warning

[B]Type safety: The method add(Object) belongs to the raw type Vector. References to generic type Vector<E> should be parameterized[/B]

What does the second part of the warning mean?

[Mike Petrogeorge]

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]

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> ();
vec.add("Hello");
[ April 12, 2007: Message edited by: P Lavti ]

[chandra reddy]

Hello Krishna

Vector takes only Objects not primitive types.

[Barry Gaunt]

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 ]