How can I validate my input is a string or not using hasnext() or hasnextline?

Question

And what is the difference between has next() method and hasnextline() method ?

Answer 1

1)First of all, if you get input through for example a Scanner, nextLine and next return a String, whatever you enter. If you input 73, it would be handled as String ("73"). So you can use hasNextLine () or hasNext (), if it's true you're able to get a String.

2)If you input this:

A line filled with words

.next () would give you "A",
.nextLine() the whole line.