Assume the following piece of code:

class A$\{$

int att$1=1$;

int att$2$;

public int method$1()\{$

return $0$;

$\}$

$\}$

public class B extends A $\{$

public int method$1()\{$

return $1$;

$\}$

$\}$

Given class A and class B$,$ what would the following lines print?

A aObj$=$new A$()$;

System.out.println$($aObj$.$att$1)$;

Group of answer choices

NullPointerException thrown

$1$

Program has no output