The java extension is non-optional

Author: eregon

lib/concurrent-ruby/concurrent/synchronization/jruby_lockable_object.rb

@@ -1,7 +1,9 @@
+require 'concurrent/utility/native_extension_loader' # load native parts first
+
 module Concurrent
   module Synchronization
 
-    if Concurrent.on_jruby? && Concurrent.java_extensions_loaded?
+    if Concurrent.on_jruby?
 
       # @!visibility private
       # @!macro internal_implementation_note

lib/concurrent-ruby/concurrent/utility/native_extension_loader.rb

@@ -15,10 +15,6 @@ def c_extensions_loaded?
         defined?(@c_extensions_loaded) && @c_extensions_loaded
       end
 
-      def java_extensions_loaded?
-        defined?(@java_extensions_loaded) && @java_extensions_loaded
-      end
-
       def load_native_extensions
         if Concurrent.on_cruby? && !c_extensions_loaded?
           ['concurrent/concurrent_ruby_ext',
@@ -50,6 +46,10 @@ def set_c_extensions_loaded
         @c_extensions_loaded = true
       end
 
+      def java_extensions_loaded?
+        defined?(@java_extensions_loaded) && @java_extensions_loaded
+      end
+
       def set_java_extensions_loaded
         @java_extensions_loaded = true
       end