JBoss AS 7.1 server is failing to deploy ear applications during the startup process regardless of the default-timeout set in deployment scanner - jboss

Question

One of our JBoss Application Server version 7.1 is failing to deploy ear applications during the startup process. I have tried many different values for the default-timeout parameter (600secs, 1200secs, 2400secs) in the deployment scanner section of the standalone.xml file. It keeps on failing with the same message no matter the value set for the default-timeout.
It used to work just fine till yesterday with the default-timeout set at 300 secs. Please find the error message in the "Error Message" section below.
Along with trying out different default-timeout values, i have also tried removing cache such as renaming or removing tmp directory several times before restarting.
What can I try to fix this?
Error Message:
15:46:01,732 ERROR [org.jboss.as.server.deployment.scanner] (DeploymentScanner-threads - 1) JBAS015052: Did not receive a response to the deployment operation within the allowed timeout period [600 seconds]. Check the server configuration file and the server logs to find more about the status of the deployment.
15:46:01,734 ERROR [org.jboss.as.server.deployment.scanner] (DeploymentScanner-threads - 1) JBAS015052: Did not receive a response to the deployment operation within the allowed timeout period [600 seconds]. Check the server configuration file and the server logs to find more about the status of the deployment.
15:46:01,733 INFO [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS015871: Deploy of deployment "ServerApps.ear" was rolled back with no failure message
15:46:01,736 ERROR [org.jboss.as.server.deployment.scanner] (DeploymentScanner-threads - 1) JBAS015052: Did not receive a response to the deployment operation within the allowed timeout period [600 seconds]. Check the server configuration file and the server logs to find more about the status of the deployment.
15:46:01,736 INFO [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS015871: Deploy of deployment "bpm.ear" was rolled back with no failure message
15:46:01,776 INFO [javax.enterprise.resource.webservices.jaxws.servlet.http] (MSC service thread 1-1) WSSERVLET15: JAX-WS servlet destroyed
15:46:01,779 INFO [javax.enterprise.resource.webservices.jaxws.server.http] (MSC service thread 1-1) WSSERVLET13: JAX-WS context listener destroyed

Answer 1

The error may cause due to the init() method of Servlet or other EE component was calling System.exit() which triggers shutdown hook to run. The JBoss Modular Service Container or MSC registers a hook and when triggered it shuts down the container. The container shutdown operation needs to wait until the EAR deployment over so that it knows if the deployment succeeded or failed. This may cause the deadlock as the System.exit() call waits until the hooks finish its execution and deadlock will be broken when the deployment gets failed due to timeout and release the MSC and continue with the shutdown.
You can try to collect the thread dumps and see if there is
A "MSC service thread" which has called into System.exit() or Runtime.exit(), and is waiting until the shutdown hooks complete.
The "MSC Shutdown Hook" thread, which is waiting for a CountDownlatch