Tomcat hang at start

I have spent about 2 days on this issue.
That is, when I trying to start up tomcat instance in Ubuntu, log tells me start up done, and I can see the tomcat process is running, I could also see the port 8080 is announced, but I am unable to connect to the host.

I find the tomcat log ends at

Deploying web application [...]

Seems like it is busy deploying the web application, but turned out it has done nothing.
After search for a while, I find an answer on SOF.

Actually, it is the random number generating thread that blocking the deployment.
The solution is to add or append an JAVA_OPT=-Djava.security.egd=file:/dev/./urandom in /etc/default/tomcat7.