class NilClass

def as_json(options = nil) #:nodoc:

:nodoc: 
def as_json(options = nil) #:nodoc:
  self
end

def blank?

nil.blank? # => true

+nil+ is blank: 
def blank?
  true
end

def duplicable?

nil.dup # => TypeError: can't dup NilClass
nil.duplicable? # => false

+nil+ is not duplicable: 
def duplicable?
  false
end

def encode_json(encoder) #:nodoc:

:nodoc: 
def encode_json(encoder) #:nodoc:
  'null'
end

def to_param

Returns +self+. 
def to_param
  self
end

def try(*args)

@person.try(:children).try(:first).try(:name)
With +try+

@person && !@person.children.blank? && @person.children.first.name
Without +try+

nil.try(:name) # => nil

It becomes specially helpful when navigating through associations that may return +nil+.
Calling +try+ on +nil+ always returns +nil+. 
def try(*args)
  nil
end

def try!(*args) 

def try!(*args)
  nil
end