Asynchronous responses in Rack
Rack is an interface for Ruby components accepting and responding to HTTP requests synchronously. Though there is not an official Rack spec for asynchronous responses, Rack servers such as Rainbows! and Thin provide an asynchronous interface for responses that may happen at an unknown time in the future, such as in a web chat room.
Bundler searches an NP-complete problem
'bundle install' may take a very long time...
The dependency resolution algorithm used in bundler (up to at least version 1.1) attempts an exhaustive search (using backtracking or backjumping) of what is an NP-complete problem. In most cases, a solution is found quickly. But in some real-world cases, the solution is not found quickly, and bundler appears to have hung.
Deploying Sonar to JBoss AS7
Sonar does not officially support the JBoss AS7 application server / servlet container (or any JBoss version). By default, JBoss's JPA modules notice the
persistence.xml file in sonar-core-2.13.1.jar!/META-INF/persistence.xml and attempt to setup JPA (Hibernate). This fails (because Sonar isn't expecting JBoss to be doing anything in the way of setting up Hibernate). One solution is to remove the JPA module from JBoss.