:: in Ruby

ruby namespace ::.rb

module Foo
  #this class is in Foo::
  class Bar
  end
  #this class is not in Foo:: but in global scope
  class ::FooBar
    #class method
    def self.method1
      'method1'
    end

    def method2
      'method2'
    end
  end
end

Foo::Bar

FooBar

FooBar::method1

FooBar.method1

FooBar::new.method2