Why will orElseThrow() not compile?

Question

I've got a project which is set up with Java 11. I have this piece of code :

Lineup lineup = (Lineup) c.list()
  .stream()
  .findFirst()
  .orElseThrow(() -> new RuntimeException("not found"));

My IDE (Netbeans 19) refuses to compile this code. The error it gives is :

unreported exception Throwable : must be caught or declared to be thrown

I've been staring at this piece of code for some time now, trying different approaches, but no matter what I do it fails to compile. My understanding is that this should work, but I must clearly be doing something wrong.

What am I doing wrong?