Q:

Wildfly: Jboss error on start-up

I am having trouble starting my jboss with      
./standalone.sh 

in the directory 
/ali/wildfly-9.0.1.Final/bin$. 

It  throws the following error
 15:01:37,824 ERROR [org.jboss.as.controller.management-operation]       
(Controller Boot Thread) WFLYCTL0013: Operation ("add") failed - address: 
([("deployment" => "HelloServlet.war")]) - failure description: 
"WFLYCTL0212: Duplicate resource [(\"deployment\" => \"HelloServlet.war
\")]"
15:01:37,830 FATAL [org.jboss.as.server] (Controller Boot Thread) 
WFLYSRV0056: Server boot has failed in an unrecoverable manner; exiting. 

A:

If you are using a deploy tool, check the standalone.xml conf file or HA conf file, at the end you should to delete the "deployments" tag
<deployments>
    <deployment name="xxx.war" runtime-name="xxx.war">
        <content sha1="fb73e5d66e5184b1d4791a5cb5d61970f73c14b0"/>
    </deployment>
</deployments>

A:

You have an error in your code.
For my case, this is what i did and it worked:
Recheck your project for errors, and correct them. Then 
clean build and deploy to wildfly using the command: mvn wildfly:deploy
Then run your project on your server (localhost:8080/HelloServlet)

A:

You will need to delete all the files in /ali/wildfly-9.0.1.Final/standalone/deployments then run the compile command again then deploy 

