I have installed Balana correctly and run mvn clean install with no error, How can I get benefit from Jar file? How can I test the policy that I have written in XACML?
Balana is just the engine. Once you Balana compiled (and presumably jarred), you need to start it and pass it the XACML policies you wrote. Now, at start-up, Balana should validate that the files are valid XACML 2.0 or XACML 3.0 files.
What you want to do next is send an authorization request using a tool e.g. SoapUI or Postman to the endpoint Balana exposes (if any that is). That will help you validate the endpoint.
PS: I have limited experience with Balana. I work mostly with Axiomatics Policy Server (disclaimer: it's where I work).
PS2: if you want to stay down the path of open source, check out AuthZForce. It's much more active.