Rank newbie here.
I wrote a "Hello world!" program in Java and ran it (in Intellij, using the little green arrow), and saw what I wanted to see.
Just to be sure, I changed the text to "Goodbye, world!" and ran it again. It greeted me with "Hello. world!". Repeated changes of the source code have not changed the output.
I am seeing Make run, and it says it built the code. The output does not change with the code. Same story when I debug.
What did I forget??