Re: class/getClass()

Daniel Pitts <>
Sun, 11 May 2008 08:31:06 -0700
Joshua Cranmer wrote:

Dennis wrote:

In class Object, getClass() returns a Class object representing
whatever object the method was called on. In something like:


protected void initialize (Class cls){

something similar appears to be happening with _class_. What is this
and where is _class_ defined? It looks like UserContext, or something
it's extending, has an attribute named _class_, but I don't see it
anywhere. Also, MyEclipse highlights this along with other java
keywords. I've poked around the language specification but couldn't
find anything about it.

The `class' keyword, when used like a static variable, returns an object
of type Class<T> (where T is the type name to which it is attached) [1].
Typically, Class objects are used for reflection purposes, although they
are occasionally used for other purposes.

[1] There is a slight bug in the Java compiler whereby List.class
returns Class<List> and not Class<List<?>> (List<?>.class does not
work); this has previously caused at least me some enormous grief.

I don't know if its a bug as much as it is a missing feature. Since
Java currently uses Type erasure, there are a lot of things it can't do...

Think about the type that would be List<Class<? extends
Foo>>.class.getClass(); Class<Class<List<Class<? extends Foo>>>>.
Whats worse is that value would .equals any other class instance. Once
(if) they make generics reifiable, the problem goes away.
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