How to make my IP publicly accessible to make my local Tomcat server public?

Yes, it is possible. It is called "Port Forwarding".

119.56.1.78 - is your public IP address.
192.168.1.1 - is your private IP address on the LAN.

To see how port forwarding is done read this very good and short tutorial with lots of nice pictures:
How to Forward Ports on Your Router

You need to do forward your 8080 port through your router.

If your IP changes (you have a dynamic IP or a static IP, this is determined by your ISP) you can get a host name from dyndns and set up your router to update dyndns with your new IP when it changes. this will allow you to access your application like so:

hostname.dynsns.org/your_app

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Alternatively, you can rent a hosted server and a domain name.

If it is for short term, you can use localtunnel (same like ngrok).

Just follow these steps (require: NodeJS):

1. Install localtunnel by running

   npm install -g localtunnel
   

2. Assumes, your app is running on http://localhost:8080/, then run

   lt --port 8080
   

   It will create a public url domain with a random name like this.

Note: You can create custom url as well (eg: lt --port 4200 -s "sangeeth", -s means subdomain).

Ta-da! It's done!