Notify java app when something has happened by another java app

Notify java app when something has happened by another java app

I want to notify my java app when a DML has occur on my DB. I can call
java.jar in the MySQL trigger with sys_exec('/path/to/javabin -jar
my.jar');
What I'm missing is how to do it JAVA-wise.
I need that my.jar will send to my general app a message(or something).
I need that my general app listen to incoming messages(but not wait for
them), open new thread and execute code.
I have no idea how to do this 2 parts.
Some people suggested semaphores, signals, messaging system. I did some
internet search with not helpful direction. I can't use 3rd party software
due.