Java: .nextLine() and .nextDouble() differences

Question

I was reading the API for Java because I had a question on the difference between .nextLine() and .nextDouble(). In the API, it says this for

Answer 1

It reads the next token (between 2 separating characters,white characters usually), not the next 4 bytes. It then transforms that token to a double if it can.

Ex: Bla bla bla 12231231.2121 bla bla.

The 4th token can be read using nextDouble(). It reads 13 chars and it transforms that string into a double if possible.