ruby - Private method and encapsulation : Prevent accidental private method overriding -

i trying understand how encapsulation mechanism works in ruby :

class     def public_method_a; p private_method; end;     private     def private_method; 'a'; end; end  class b <     def public_method_b; p private_method; end;     private     def private_method; 'b'; end; end 

now when try run code, here :

1. > a.new.public_method_a => "a" 2. > b.new.public_method_b => "b" 3. > b.new.public_method_a => "b" 

basically, third call refers private method defined in b , not in a. java developer's point of view, encapsulation violation. call private_method should refer method defined in class call made. in ruby, seems more matter of context. right ?

how can make sure private methods never called outside respective class ? doing wrong ?

thank in advance help.

nutshell: private means message can't have explicit receiver.

that's all; nothing more.

it removes message public api, nothing regarding subclasses , on.

protected means instances , sub-class instances can call method, e.g., can't call outside inheritance tree.

note both trivially subverted via send.

nice summary of private , protected in ruby