what's the vertical line coloured by green on the bottom of the run button in IntelliJ?

Question

enter image description here I am quite doubtful what dose the green line in the white circle that I just marked mean by? Moreover output didn't work when I tried to run it! how can I solve it?

enter image description here

Answer 1

You are using a version control system (Git, perhaps?) to keep track of the changes to your code.

The green bar indicates "This line was added since the last time you committed your changes". Likewise, a blue bar means "This line has been changed since the last commit" and a small gray arrow indicates "One or more lines have been removed from here since the last commit".

This bar does not affect your code or indicate errors or problems. It's only there to inform you which parts of the code you've changed so far and which ones are the same as before.

As for your second question, Stack Overflow discourages users from asking multiple unrelated questions in the same post. You are better off asking that in a separate post.