Purpose of a here?

Question

Int x;
Scanner a= new Scanner (System.in);
x= a.nextInt();

Answer 1

you can take multiple inputs using single Scanner object a, no need of making more objects of Scanner class, like this :
int x=a.nextInt(); //i small in int
int y=a.nextInt();
String str=a.next();

Answer 2

It's initializing a Scanner object called a ( could be called also with another name), showing that we're going to read user input. You can read about this here:https://www.sololearn.com/learn/Java/2220/