You don't need any IDE?

I was going through the Head-First book and found something strange.

Check this one out.

You do not need any other development tool. such as an Integrated
Development Environment (IDE). We strongly recommend that you not
use anything but a-basic text editor until you complete this book (and
especially not until after chapter 16). An IDE can protect you from some of the details that really matter. so you're much bener off learning from the command-line and then. once you really understand what's happening. move to a tool that automates some of the process.

Cool ah?

I will follow that.