Question

If user passes a primitive type argument to println(), what exactly happens behind the scene? e.g.

int i =1;

System.out.println("My Int"+i);

//and in

System.out.println(i)

How does it print "My Int 1" and "1", even though it needs a String object?

updated..

What I think is AutoBoxing comes into play. Is that true, too?

Answer 1

It does not need a String object, and there is no autoboxing at play here, either. There are methods for primitive types as well:

public void print(int i)

Print an integer. The string produced by String.valueOf(int) is translated into bytes according to the platform’s default character encoding, and these bytes are written in exactly the manner of the write(int) method.