Thanks :)
Since the JRuby operation seems odd and I don't know how it works, I decided to uninstall asciidoctor from my laptop in order to do some tests: 
```shell
gem uninstall asciidoctor
```

Then I do the following tests :

- WildFly AS (default conf) + Asciidoctor 0.1.4 embedded in my WAR => KO
- WildFly AS + module Asciidoctor 0.1.4 + WAR without embedded libraries => **OK**
- JBoss EAP 6.1.1 (JBoss AS 7.2.1) and Asciidoctor 0.1.4 embedded in my WAR => KO
- JBoss EAP 6.1.1 (JBoss AS 7.2.1) + module Asciidoctor 0.1.4 + WAR without embedded libraries => **OK**
- I tried a last test with WildFly and Asciidoctor 0.1.4 embedded in my WAR :
When the deployed WAR embed Asciidoctor 0.1.4, WildFly starts with the followings warnings :

```text
2013-11-17 15:05:03,279 WARN  [org.jboss.as.server.deployment] (MSC service thread 1-5) JBAS015960: Class Path entry libs/jruby-complete-1.7.4.jar in /content/websocket-met-asciidoctor.war/WEB-INF/lib/asciidoctor-java-integration-0.1.4.jar  does not point to a valid jar for a Class-Path reference.
2013-11-17 15:05:03,280 WARN  [org.jboss.as.server.deployment] (MSC service thread 1-5) JBAS015960: Class Path entry libs/jcommander-1.30.jar in /content/websocket-met-asciidoctor.war/WEB-INF/lib/asciidoctor-java-integration-0.1.4.jar  does not point to a valid jar for a Class-Path reference.
```
In fact, the Asciidoctor MANIFEST.MF file contains this entry (required for the cli) :
```text
Class-Path: libs/jruby-complete-1.7.4.jar libs/jcommander-1.30.jar
```
And I think that it can be a problem for the application classloader. So I delete this line and I deploy the WAR with asciidoctor.jar updated but that doesn't solve the problem.