diff --git a/racc.gemspec b/racc.gemspec
index 1095c8f..ef8f1c8 100644
--- a/racc.gemspec
+++ b/racc.gemspec
@@ -48,11 +48,4 @@ DESC
   s.required_ruby_version = ">= 2.5"
   s.rdoc_options = ["--main", "README.rdoc"]
   s.extra_rdoc_files = ["README.ja.rdoc", "README.rdoc"]
-
-  if RUBY_PLATFORM =~ /java/
-    s.files << 'lib/racc/cparse-jruby.jar'
-    s.platform = 'java'
-  else
-    s.extensions = ["ext/racc/cparse/extconf.rb"]
-  end
 end
