Cool class and method names wrapped in ``: class `This is a cool class` {}?

Question

I just found some scala code which has a strange class name:

 class `This is a cool class` {}

and method name:

 def `cool method` = {}

We can use a sentence for a class or method name!

It's very cool and useful for unit-testing:

class UserTest {
   def `user can be saved to db` {
      // testing
   }
}

But why we can do this? How to understand it?

Answer 1

This feature exists for the sake of interoperability. If Scala has a reserved word (with, for example), then you can still refer to code from other languages which use it as a method or variable or whatever, by using backticks.

Since there was no reason to forbid nearly arbitrary strings, you can use nearly arbitrary strings.

Answer 2

As @Rex Kerr answered, this feature is for interoperablility. For example,

To call a java method,

Thread.yield()

you need to write

Thread.`yield`()

since yield is a keyword in scala.