Performance improvements for concurrent-ruby's Executor

gistfile1.diff

diff --git a/lib/concurrent/executor/executor.rb b/lib/concurrent/executor/executor.rb
index d97b537..82cdb67 100644
--- a/lib/concurrent/executor/executor.rb
+++ b/lib/concurrent/executor/executor.rb
@@ -290,12 +290,23 @@ module Concurrent
           caller_runs: java.util.concurrent.ThreadPoolExecutor::CallerRunsPolicy
       }.freeze
 
+      class Job
+        include Runnable
+        def initialize(args, block)
+          @args = args
+          @block = block
+        end
+
+        def run
+          @block.call(*@args)
+        end
+      end
+
       # @!macro executor_method_post
       def post(*args, &task)
         raise ArgumentError.new('no block given') unless block_given?
         return handle_fallback(*args, &task) unless running?
-        executor_submit = @executor.java_method(:submit, [Runnable.java_class])
-        executor_submit.call { yield(*args) }
+        @executor.submit_runnable Job.new(args, task)
         true
       rescue Java::JavaUtilConcurrent::RejectedExecutionException
         raise RejectedExecutionError
diff --git a/lib/concurrent/executor/java_single_thread_executor.rb b/lib/concurrent/executor/java_single_thread_executor.rb
index 7931734..dd6e54b 100644
--- a/lib/concurrent/executor/java_single_thread_executor.rb
+++ b/lib/concurrent/executor/java_single_thread_executor.rb
@@ -20,6 +20,11 @@ if Concurrent.on_jruby?
       # @see http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ExecutorService.html
       def initialize(opts = {})
         @executor = java.util.concurrent.Executors.newSingleThreadExecutor
+        if !defined?(@executor.submit_runnable)
+          @executor.class.class_eval do
+            java_alias :submit_runnable, :submit, [java.lang.Runnable.java_class]
+          end
+        end
         @fallback_policy = opts.fetch(:fallback_policy, :discard)
         raise ArgumentError.new("#{@fallback_policy} is not a valid fallback policy") unless FALLBACK_POLICIES.keys.include?(@fallback_policy)
         self.auto_terminate = opts.fetch(:auto_terminate, true)
diff --git a/lib/concurrent/executor/java_thread_pool_executor.rb b/lib/concurrent/executor/java_thread_pool_executor.rb
index d9ba7c5..8811141 100644
--- a/lib/concurrent/executor/java_thread_pool_executor.rb
+++ b/lib/concurrent/executor/java_thread_pool_executor.rb
@@ -75,6 +75,11 @@ if Concurrent.on_jruby?
           min_length, max_length,
           idletime, java.util.concurrent.TimeUnit::SECONDS,
           queue, FALLBACK_POLICIES[@fallback_policy].new)
+        if !defined?(@executor.submit_runnable)
+          @executor.class.class_eval do
+            java_alias :submit_runnable, :submit, [java.lang.Runnable.java_class]
+          end
+        end
 
         self.auto_terminate = opts.fetch(:auto_terminate, true)
       end