How to create method and how to call it?

Answer 1

Learn all the lesson in Java Course, and you will know how to do it.

Answer 2

method is like

public int sum(int x){
return ++x;
}

in the same class or another one,

to call it, if it's in the same class
type:

sum(any number to do summation);

if it's in another class, u have to create an object

anotherclass object = new anotherclass;

then call like this
object.sum(any number) ;