diff --git a/lib/execjs/johnson_runtime.rb b/lib/execjs/johnson_runtime.rb
index 75c980a..4beb954 100644
--- a/lib/execjs/johnson_runtime.rb
+++ b/lib/execjs/johnson_runtime.rb
@@ -5,7 +5,7 @@ module ExecJS
     class Context < Runtime::Context
       def initialize(runtime, source = "")
         source = encode(source)
-        
+
         @runtime = Johnson::Runtime.new
         @runtime.evaluate(source)
       end
diff --git a/lib/execjs/ruby_racer_runtime.rb b/lib/execjs/ruby_racer_runtime.rb
index 0c573fa..fab327e 100644
--- a/lib/execjs/ruby_racer_runtime.rb
+++ b/lib/execjs/ruby_racer_runtime.rb
@@ -94,7 +94,7 @@ module ExecJS
     def name
       "therubyracer (V8)"
     end
-    
+
     def available?
       require "v8"
       true
diff --git a/lib/execjs/ruby_rhino_runtime.rb b/lib/execjs/ruby_rhino_runtime.rb
index 0b45be3..65c3908 100644
--- a/lib/execjs/ruby_rhino_runtime.rb
+++ b/lib/execjs/ruby_rhino_runtime.rb
@@ -78,7 +78,7 @@ module ExecJS
     def name
       "therubyrhino (Rhino)"
     end
-    
+
     def available?
       require "rhino"
       true
diff --git a/lib/execjs/runtime.rb b/lib/execjs/runtime.rb
index bb33b46..92603f4 100644
--- a/lib/execjs/runtime.rb
+++ b/lib/execjs/runtime.rb
@@ -12,7 +12,7 @@ module ExecJS
       def exec(source, options = {})
         raise NotImplementedError
       end
-      
+
       def eval(source, options = {})
         raise NotImplementedError
       end
@@ -25,7 +25,7 @@ module ExecJS
     def name
       raise NotImplementedError
     end
-    
+
     def context_class
       self.class::Context
     end