I thought we had added logic to net/http to honor this. Perhaps it was lost?

Are you taking about this? #195 or d04857c#diff-49

I confirmed that Net::HTTP can ignore http.proxyHost at 2.0 mode.
However, I hope that Net::HTTP change operation in response to http.nonProxyHosts, because I think that http.proxyHost, http.proxyPort, and http.nonProxyHosts are one set.
I have no idea...

I do see the same logic (using ENV_JAVA['http.proxyHost'] etc) in 2.0 mode's net/http. How are you initiating an HTTP connection?

...
    #
    # In JRuby, this will default to the JSE proxy settings provided in the
    # 'http.proxyHost' and 'http.proxyPort' Java system properties, if they
    # are set and no alternative proxy has been provided.
    #
    def HTTP.new(address, port = nil, p_addr = ENV_JAVA['http.proxyHost'], p_port = ENV_JAVA['http.proxyPort'], p_user = nil, p_pass = nil)
      http = super address, port

      if proxy_class? then # from Net::HTTP::Proxy()
...

I'm using ActiveResource.
ActiveResoruce create Net::HTTP instance by Net::HTTP.new(@site.host, @site.port), when I use without proxy.
https://github.com/rails/activeresource/blob/v4.0.0/lib/active_resource/connection.rb#L172

ex)

#main.rb
require 'bundler'
Bundler.require
require 'active_resource'

# for debug
class ActiveResource::Connection
  alias_method :new_http_without_debug, :new_http
  def new_http(*args)
    new_http_without_debug(*args).tap{|h| h.set_debug_output($stderr)}
  end
end

# my model
class MyModel < ActiveResource::Base
  self.site = 'http://localhost:9292'
  self.proxy = nil
end

p RUBY_VERSION
if defined?(ENV_JAVA)
  p ENV_JAVA.values_at *%w(http.proxyHost http.proxyPort http.nonProxyHosts)
end
p MyModel.all

$ jruby main.rb 
"1.9.3"
["xxx.example.com", "8080", "localhost|*.localhost]
opening connection to xxx.example.com...
opened
<- "GET http://localhost:9292/my_models.json HTTP/1.1\r\nAccept: application/json\r\nAccept-Encoding: gzip;q=1.0,deflate;q=0.6,identity;q=0.3\r\nUser-Agent: Ruby\r\nConnection: close\r\nHost: localhost:9292\r\n\r\n"

2.0 mode has the same result.

Ok, so if I understand right, the proxy is being used, but it's not being ignored based on your ignore spec...correct?

So here's what I think we need to do.

1. Net::HTTP.new needs to gain a parameter for non proxy hosts. Currently it does support them (via find_proxy in generic.rb) but only from the no_proxy ENV var. It seems a reasonable additional parameter, since the last four params are all setting up a proxy.
2. Modify find_proxy to also check the JVM properties. I have a patch in progress now that tries http_proxy and no_proxy from ENV, falling back on the ENV_JAVA values.

The first change will take some time to get into Ruby versions, and will need to be filed with ruby-core at http://bugs.ruby-lang.org. Luckily, I'm also a ruby-core committer so I should be able to help usher it through.

The second change can be done in any version of JRuby, but I'm working on doing it in such a way that it doesn't break the current logic for defaulting to ENV_JAVA values.

I believe I have (2)[https://github.com//issues/2983#issuecomment-106601849] above implemented. Here's the output from your script before and after my change, with http.proxyHost set (note that http.nonProxyHosts defaults to all loopback and private network addresses):

Before:

[] ~/projects/jruby-1.7 $ jruby --2.0 -J-Dhttp.proxyHost=foobar.com blah.rb
"2.0.0"
["foobar.com", nil, "local|*.local|169.254/16|*.169.254/16|127.0.0.1|localhost|*.localhost"]
opening connection to foobar.com:80...
opened

After:

[] ~/projects/jruby-1.7 $ jruby --2.0 -J-Dhttp.proxyHost=foobar.com blah.rb
"2.0.0"
["foobar.com", nil, "local|*.local|169.254/16|*.169.254/16|127.0.0.1|localhost|*.localhost"]
opening connection to localhost:9292...

Here's the diff. We'd apply this to net/http and uri/generic for all versions: https://gist.github.com/headius/6272d168cf165ddf675f

I have filed a bug with MRI to get my changes incorporated, in whole or in part, back into MRI stdlib: https://bugs.ruby-lang.org/issues/11194

I filed a separate issue to add a no_proxy param to HTTP.new: https://bugs.ruby-lang.org/issues/11195

It's the behavior that I wanted.
Until it is fixed, I use code of applying your diff.
Thank you so much. 😄

I will apply the diff to JRuby 1.7 and 9k for next releases, and work separately with MRI to get the changes upstream.

Ok, so the problem I run into is that the ENV support in net/http did not arrive until 2.0, so the 1.9 net/http.rb and uri/generic.rb do not have the code needed for this.

We can apply to the 2.0 stdlib, but we have generally not backported code that ruby-core has not opted to backport themselves. JRuby 1.7.21 will support it in the (experimental) 2.0 mode and JRuby 9k will support it normally.

thank you. 👍