What exactly is this?
Do i have to do some configuration to achieve it or its already implemented in jboss.
How can i achieve 1000-10000 concurrent connections?
How can i test concurrent connections?
Could you provide some context? In other words, where did you see the term "hybrid connection model".
To achieve the number of concurrent connections you mention you usually need to run multiple jbossas instances.
For testing, you could use JMeter or Grinder, or you could go with one of a number of commercial products (whose names escape me).