table.rb

class Table
  class << self
    def say_goodbye
      puts "goodbye"
    end

    def count
      @@count ||= 0
    end

    def increment_table_count
      Table.say_hello
      @@count = count + 1
    end

    def decrement_table_count
      self.say_goodbye
      @@count -= 1
    end
  end

  def self.say_hello
    puts "hello"
  end

  def initialize
    Table.increment_table_count
  end

  def self.finalize(table)
    proc { Table.decrement_table_count }
  end
end

puts Table.count
t1 = Table.new
puts Table.count
t1 = nil

GC.start
puts Table.count