JBOSS not running - linux

Question

I'm from Linux server background and very new to JBOSS. I'm trying to setup a IoT application server which requires JBOSS service to provide
a web interface for the application server.
But when i check the JBOSS server state it is showing 'starting', i need this to be 'running'.
# /opt/cgms/bin/jboss-cli.sh --connect controller=127.0.0.1 ":read- attribute(name=server-state)"
{
"outcome" => "success",
"result" => "starting"
}
I can see that the deployment is getting failed when i start JBOSS using the script standalone.sh. I've increased the deployment-timeout
up to 6000 seconds in standalone.xml, still the deployment is failing with the following message in /opt/cgms/standalone/deployments/cgms.ear.failed,
""JBAS015052: Did not receive a response to the deployment operation within the allowed timeout period [6000 seconds].
Check the server configuration file and the server logs to find more about the status of the deployment."
Here is my JBOSS setup details,
[root#app-server ~]# /opt/cgms/bin/jboss-cli.sh --connect
[standalone#localhost:9999 /] version
JBoss Admin Command-line Interface
JBOSS_HOME: /opt/cgms
JBoss AS release: 7.3.0.Final-redhat-14 "Janus"
JBoss AS product: EAP 6.2.0.GA
JAVA_HOME: null
java.version: 1.8.0_65
java.vm.vendor: Oracle Corporation
java.vm.version: 25.65-b01
os.name: Linux
os.version: 3.10.0-229.el7.x86_64
When i check the server.log, it is stuck at,
# tailf /opt/cgms/server/cgms/log/server.log
624: app-server: Aug 12 2017 05:45:01.506 +0000: %IOTFND-6-UNSPECIFIED: %[ch=StdSchedulerFactory][sev=INFO][tid=MSC service thread 1-1]: Quartz scheduler 'CgnmsQuartz' initialized from an externally provided properties instance.
625: app-server: Aug 12 2017 05:45:01.506 +0000: %IOTFND-6-UNSPECIFIED: %[ch=StdSchedulerFactory][sev=INFO][tid=MSC service thread 1-1]: Quartz scheduler version: 2.2.1
It will not go further from here.
I've tried with java 1.7, but the script standalone.sh failed with a java error,
java.lang.UnsupportedClassVersionError: com/cisco/cgms/loglayout/LogHandler : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at org.jboss.modules.ModuleClassLoader.doDefineOrLoadClass(ModuleClassLoader.java:345)
at org.jboss.modules.ModuleClassLoader.defineClass(ModuleClassLoader.java:423)
at org.jboss.modules.ModuleClassLoader.loadClassLocal(ModuleClassLoader.java:261)
at org.jboss.modules.ModuleClassLoader$1.loadClassLocal(ModuleClassLoader.java:76)
Here are my server details,
OS - Red Hat Enterprise Linux Server release 7.1 (Maipo) - runs on Oracle VM VirtualBox
kernel - app-server 3.10.0-229.el7.x86_64 #1 SMP Thu Jan 29 18:37:38 EST 2015 x86_64 x86_64 x86_64 GNU/Linux
When i check netstat, port 80 and 443 are listening.
Please help to fix this problem.