Write a programming giving an ALERT

I have a program, written I believe in Java code, that gives a continuous series of numbers (quotes on a market). It is similar in this sense to Reuters 3000.

However, I do not have the alert function on this program, it is a simpler one.

Generally speaking, would it be possible to write a simple JAVA program that constrains the computer to emit a sound or an image when, eg, these quotes go up or down?

Eg an arrow pointing up or down...

Thank you very much for your help! It would be very much appreciated....

Yes