int a = sc.nextInt(); // taking an integer as input and placing it in integer variable a // .nextInt() to take an integer as input, similarly, .next(), .nextByte ...

Java's ability in terms of functional programming is close to zero sadly. In many cases you will be forced to create a class that really represents a function for example.

Want to know more about standard Java I/O concepts like standard input, standard output, and standard error? Read on!