What is the point of final class in Java

Question

I am reading a book about Java and it says that you can declare the whole class as final. I cannot think of anything where I'd use this.

I am just new to programming and I am wondering if programmers actually use this on their programs. If they do, when do they use it so I can understand it better and know when to use it.

If Java is object oriented, and you declare a class final, doesn't it stop the idea of class having the characteristics of objects?