10 Things Every Java Programmer Should Know About Ruby

No Primitives!

Even integers are full fledged objects.

  0.zero?    # => true
  1.zero?    # => false
  1.abs      # => 1
  -1.abs     # => 1
  1.methods  # => list of methods for object 1
  2.+(3)     # => 5  (same as 2+3)
  10.class   # => Fixnum
  (10**100).class
             # => Bignum