3 files changed, 11 insertions, 5 deletions
diff --git a/activesupport/lib/active_support/json/decoding.rb b/activesupport/lib/active_support/json/decoding.rb
index 0e079341ff..c66500aa9c 100644
--- a/activesupport/lib/active_support/json/decoding.rb
+++ b/activesupport/lib/active_support/json/decoding.rb
@@ -1,5 +1,7 @@
-require 'yaml'
-require 'strscan'
+autoload :YAML, 'yaml' unless defined? YAML
+autoload :StringScanner, 'strscan' unless defined? StringScanner
+
+require 'active_support/core_ext/string/starts_ends_with'
 
 module ActiveSupport
   module JSON
@@ -45,7 +47,7 @@ module ActiveSupport
           if marks.empty?
             json.gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do
               ustr = $1
-              if ustr.starts_with?('u')
+              if ustr.start_with?('u')
                 [ustr[1..-1].to_i(16)].pack("U")
               elsif ustr == '\\'
                 '\\\\'
@@ -61,10 +63,10 @@ module ActiveSupport
               scanner.pos = left.succ
               output << scanner.peek(right_pos[i] - scanner.pos + 1).gsub(/\\([\\\/]|u[[:xdigit:]]{4})/) do
                 ustr = $1
-                if ustr.starts_with?('u')
+                if ustr.start_with?('u')
                   [ustr[1..-1].to_i(16)].pack("U")
                 elsif ustr == '\\'
-                '\\\\'
+                  '\\\\'
                 else
                   ustr
                 end
diff --git a/activesupport/lib/active_support/json/encoders/hash.rb b/activesupport/lib/active_support/json/encoders/hash.rb
index e38b4f3e16..d87b880743 100644
--- a/activesupport/lib/active_support/json/encoders/hash.rb
+++ b/activesupport/lib/active_support/json/encoders/hash.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/array/wrap'
+
 class Hash
   # Returns a JSON string representing the hash.
   #
diff --git a/activesupport/lib/active_support/json/encoders/object.rb b/activesupport/lib/active_support/json/encoders/object.rb
index ca215d4964..0475967aee 100644
--- a/activesupport/lib/active_support/json/encoders/object.rb
+++ b/activesupport/lib/active_support/json/encoders/object.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/object/instance_variables'
+
 class Object
   # Dumps object in JSON (JavaScript Object Notation). See www.json.org for more info.
   def to_json(options = {})