5 files changed, 20 insertions, 5 deletions
diff --git a/activejob/lib/active_job/callbacks.rb b/activejob/lib/active_job/callbacks.rb
index 8901fa77f2..cafa3438c0 100644
--- a/activejob/lib/active_job/callbacks.rb
+++ b/activejob/lib/active_job/callbacks.rb
@@ -3,8 +3,8 @@ require 'active_support/callbacks'
 module ActiveJob
   # = Active Job Callbacks
   #
-  # Active Job provides hooks during the lifecycle of a job. Callbacks allow you to trigger
-  # logic during the lifecycle of a job. Available callbacks:
+  # Active Job provides hooks during the lifecycle of a job. Callbacks allow you
+  # to trigger logic during the lifecycle of a job. Available callbacks are:
   #
   # * <tt>before_enqueue</tt>
   # * <tt>around_enqueue</tt>
diff --git a/activejob/lib/active_job/gem_version.rb b/activejob/lib/active_job/gem_version.rb
index 2545e09845..1f25d48326 100644
--- a/activejob/lib/active_job/gem_version.rb
+++ b/activejob/lib/active_job/gem_version.rb
@@ -8,7 +8,7 @@ module ActiveJob
     MAJOR = 4
     MINOR = 2
     TINY  = 0
-    PRE   = "alpha"
+    PRE   = "beta1"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/activejob/lib/active_job/queue_adapter.rb b/activejob/lib/active_job/queue_adapter.rb
index 8f2f8b86ea..13c23abce4 100644
--- a/activejob/lib/active_job/queue_adapter.rb
+++ b/activejob/lib/active_job/queue_adapter.rb
@@ -17,7 +17,6 @@ module ActiveJob
 
     private
       def load_adapter(name)
-        require "active_job/queue_adapters/#{name}_adapter"
         "ActiveJob::QueueAdapters::#{name.to_s.camelize}Adapter".constantize
       end
   end
diff --git a/activejob/lib/active_job/queue_adapters.rb b/activejob/lib/active_job/queue_adapters.rb
new file mode 100644
index 0000000000..007068ff0a
--- /dev/null
+++ b/activejob/lib/active_job/queue_adapters.rb
@@ -0,0 +1,16 @@
+module ActiveJob
+  module QueueAdapters
+    extend ActiveSupport::Autoload
+
+    autoload :InlineAdapter
+    autoload :BackburnerAdapter
+    autoload :DelayedJobAdapter
+    autoload :QuAdapter
+    autoload :QueAdapter
+    autoload :QueueClassicAdapter
+    autoload :ResqueAdapter
+    autoload :SidekiqAdapter
+    autoload :SneakersAdapter
+    autoload :SuckerPunchAdapter
+  end
+end
diff --git a/activejob/lib/active_job/queue_adapters/backburner_adapter.rb b/activejob/lib/active_job/queue_adapters/backburner_adapter.rb
index 8d34155645..8ebee36e45 100644
--- a/activejob/lib/active_job/queue_adapters/backburner_adapter.rb
+++ b/activejob/lib/active_job/queue_adapters/backburner_adapter.rb
@@ -9,7 +9,7 @@ module ActiveJob
         end
 
         def enqueue_at(job, timestamp, *args)
-          delay = Time.current.to_f - timestamp
+          delay = timestamp - Time.current.to_f
           Backburner::Worker.enqueue JobWrapper, [ job.name, *args ], queue: job.queue_name, delay: delay
         end
       end