Java beginner need help

Question

can someone explain why output is 5 not 6 ?(in the simplest way possible i'm quite dumb)

public class MyClass {
public static void main(String[ ] args) {
int x = 5;
addOneTo(x);
System.out.println(x);
}
static void addOneTo(int num) {
num = num + 1;
}
}
// Outputs "5"

Answer 1

For primitive types like int, double, char etc., when a variable is passed to a method, actually a COPY (value) of the variable is passed. So whatever you'll do inside that method, it won't affect the original variable.

Calling the method will pass 5 (value) to it, it won't pass x. If you print num inside the method, it will print 6. But x will remain as it was.