hasNext() - when does it block and why?

Question

I\'m trying to read commands via a Scanner Object. For checking the Input Syntax I use sc.hasNext() (for the case of missing commands). It did work

Answer 1

I'm not sure , but the following is my own experience :
when the Scanner object is fed with a file , it will not be blocking !
By the term "fed with a file " I mean that the scanner is constructed like this :
Scanner scanner = new Scanner("myFile.txt");

But if the scanner is constructed using the getInputStream()method of a Socket object , like this :

input = socket.getInputStream();
Scanner scanner = new Scanner(input);

the scanner will be blocking !