Try changing the port,
Change JENKINS_AJP_PORT="xyz" to JENKINS_AJP_PORT="abc"
If changing the ports did not solve the problem, then the error is mostly coming from the version of Java installed,
Updating java-1.7.0-openjdk to java-1.8.0-openjdk will do the trick
Use the following command to install java 8
sudo yum install java-1.8.0-openjdk
Make sure you remove the older version of java. Use the following command to do so.
sudo yum remove java-1.7.0-openjdk.x86_64
Finally, restart jenkins service, use the following command
sudo service jenkins restart