Eclipse: HTTP Proxy Authentication Required

Eclipse Luna 4.4.0 has a bug when using Proxy to contact to Internet:
(upgrade to 4.4.1 --> Luna SR1)

i.e.:

HTTP Proxy Authentication Required: http://download.eclipse.org/modeling/tmf/xtext/updates/composite/releases/compositeContent.xml
HTTP Proxy Authentication Required: http://download.eclipse.org/modeling/tmf/xtext/updates/composite/releases/compositeContent.xml
Proxy Authentication Required

This is a known bug:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=422665
https://www.eclipse.org/forums/index.php/t/783720/

A functional workaround is:
(provided in the first URL)

Scott Lewis 2014-07-08 17:51:00 EDT I've created an updated version of the ECF httpclient4 provider that uses Apache Httpclient 4.1 (used in Kepler) rather than Apache Httpclient 4.2 (used in Luna  and the apparent source of this regression). For those that are experiencing this proxy problem, this update may allow you to  use your proxy, especially if Kepler (Apache 4.1) install/update worked for you.  If it *does* work in some of your environments, then it would suggest that the problem  is not with proxy configuration, but rather with Apache httpclient 4.2 deployed as part  of Luna. OTOH if this does not fix things for you, then it may very well be a  configuration issue. Disclaimer: Installing this update, and going back to using an older version of  httpclient4, could break other plugins. Even if it works in your environment,  please do not use it in a production environment unless you are quite sure that  nothing else is broken by it (e.g. Mylyn). Also, this repo is not signed so please  do not redistribute it. If you are not experiencing any problem wrt this bug,  please do not install it. People on this bug who install and try this in their proxy environment please report  back with what happens via a new comment on this bug. Since I do not have an  environment to reproduce this apparent httpclient4 version-specific problem, I must  depend upon people on this bug that do have such an environment for diagnosis. Instructions for installation: 1) Download this zip: http://download.eclipse.org/rt/ecf/httpclient4/org.eclipse.ecf.provider.httpclient4_3.9.0.zip 2) Unzip the contents to your local disk 3) Start Eclipse Luna. 4) Choose Help->Install New Software->Add... 5) Name: ECF 3.9.0 Httpclient4 Update 6) Select Local... button on right and navigate your local filesystem to where  you unzipped the contents to in step 2 7) Navigate into the /archive/site.p2 directory and choose OK 8) There should be a single 'Uncategorized' item in the user Install dialog.  Select this check box (and all sub-items) 9) Choose Next and step through the remaining wizard pages to finish the install 10) Restart Eclipse when prompted Then please try to install something into Eclipse. Whether this works for you  or not, it would be helpful for you to report your experiences here with as  much detail as possible. Thanks.