Spring Boot with Tomcat not starting on Centos 7

Question

I'm fighting with a strange problem for a couple of days now and I am ready to give up and move to different VPS provider.

In short, spring boot with tomcat (both jar or CLI) is not starting properly on CentOS 7 (DigitalOcean). No errors, but it does not get to the listening part.

Some context:

• Fresh VPS with CentOS 7 on DigitalOcean
• I have tried openjdk 7/8, oracle jdk 7/8 - same result
• tried both with a "fat" jar and using cli (spring run a.groovy)
• I suspect it's related to multiple network cards and/or IPV6
• I have tried java -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Addresses -jar a.jar --server.address=IP
• Works with embedded Jetty!
• tomcat 7/8 (both yum and direct downloaded) standalone works fine
• same thing works on my local machine (I use CentOS 7 too)
• same thing works on Linode VPS (different kernel and ifconfig though)
• DigitalOcean support tried to help, but it's a "software" issue

Please see below a few samples:

a.groovy

@RestController
class WebApplication {
    @RequestMapping("/")
    String home() {
        "Hello World!"
    }
}

log output from spring run a.groovy -v

2016-01-16 03:23:20.731  INFO 19507 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-01-16 03:23:20.732  INFO 19507 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-01-16 03:23:20.732  INFO 19507 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-01-16 03:23:20.732  INFO 19507 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-01-16 03:23:20.732 DEBUG 19507 --- [ost-startStop-1] o.apache.catalina.core.StandardContext   : Configuring application event listeners
2016-01-16 03:23:20.732 DEBUG 19507 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       :  Configuring event listener class 'org.apache.tomcat.websocket.server.WsContextListener'
2016-01-16 03:23:20.734 DEBUG 19507 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Sending application start events
2016-01-16 03:23:20.756 DEBUG 19507 --- [ost-startStop-1] org.apache.tomcat.util.modeler.Registry  : Managed= Tomcat:type=Manager,host=localhost,context=/
2016-01-16 03:23:20.756 DEBUG 19507 --- [ost-startStop-1] o.a.tomcat.util.modeler.BaseModelMBean   : preRegister org.apache.catalina.session.StandardManager[] Tomcat:type=Manager,host=localhost,context=/

Thank you in advance.