I've learnt java basics till arrays. I want to proceed further but I'm unclear about what topics to study. Please list out the topics to work on after basics in detail.

What does hasNext() and next() do in java? Can you please give some examples?

I was stuck with the scanner and the method in it. hasNext() and next() methods. I want a simple and detailed explanation of these.

Can I learn data structures and algorithms if I have no coding experience? Where can I learn data structures for free online?

how to generate random alphabets in java?

How can I generate random Alphabets using java code?

I wanna know how to generate random alphabets. I'm already familiar with generating random consecutive numbers.