diff --git a/deploy/lib/server_config.rb b/deploy/lib/server_config.rb
index 364b473c..ddbbe064 100644
--- a/deploy/lib/server_config.rb
+++ b/deploy/lib/server_config.rb
@@ -199,7 +199,6 @@ def ServerConfig.strip_path(path)
   end
 
   def self.jar
-    raise HelpException.new("jar", "You must be using JRuby to create a jar") unless RUBY_PLATFORM == "java"
     begin
       # ensure warbler gem is installed
       gem 'warbler'
diff --git a/deploy/lib/util.rb b/deploy/lib/util.rb
index 6aa73a87..4e6f2cf2 100644
--- a/deploy/lib/util.rb
+++ b/deploy/lib/util.rb
@@ -88,7 +88,7 @@ def path_separator
 end
 
 def is_jar?
-  __FILE__.match(/.*\.jar.*/) != nil
+  RUBY_PLATFORM == "java"
 end
 
 def copy_file(src, target)