Ever heard of React in the java context?
Java as in the computer software?  No I don't know anything more than the term Java.  What is react?
React is basically a javascript library for building user interfaces.
Does that mean you can write a program with script others have already made meaning you don't have to do as much work?
I believe so. It makes making user interfaces much simpler.
That sounds useful.  Have any well known apps/programs used react?
Well I know that both Instagram and Facebook use React.