Ruby craziness: Class vs Object?

Question

I just started playing with JRuby. This is my first ruby post. I had a hard time understanding classes vs objects in Ruby. It doesnt mean like what classes & objects in other Object oriented laguages. for an example

Class.is_a? Object

returns true and

Object.is_a? Object

too.

so class & Object are both objects

here comes another one

Class.is_a? Class

returns true and

Object.is_a? Class

too.

wait, i am not done yet

 Object.instance_of? Class
 Class.instance_of? Class

Both are true

 Object.instance_of? Object
 Class.instance_of? Object

Both are false. right, nothing can be instance of object.

And

 Class.kind_of? Class
 Object.kind_of? Class

both are true

 Class.kind_of? Object
 Object.kind_of? Object

both are true

So both are exactly same, then why do we have both these.?

After some more digging, i wrote this simple method to return method list supported by both

irb(main):054:0> def print_methods(obj)
irb(main):055:1>    obj.methods.each do |mm|
irb(main):056:2*        puts mm
irb(main):057:2>    end
irb(main):058:1> end

Only method difference between print_methods(Object) and print_methods(Class) is

     Nesting

if Nesting means inheritance, Is Object similar to the sealed class??

Can someone clarify me what is all this?

Update: To Edds comment

Interestingly i see lot of differences in the method list in

c=Class.new
print_methods(c)

&

o=Object.new
print_methods(o)

Now I understand Instance of a class is really an class instance (And this class instance is actually a Object) not an object instance. And even this instance allow me to span another instances

  xx = c.new //works - c is an Object / and xx is a instance of an Object c
  yy = o.new //nope  - o is already a instance of an Object, so it cannot be instantiated again

So Finally, Object is really an instance of a Class. Because

  xx.is_a? Class 

is false, but

  xx.is_a? Object 

returns true

Am i right, ??

Answer 1

Think of Classes as global objects.