What is the output of this Java program?

Class Driver $\{$

public static void main$($String$[]$ args$)\{$

foo $(2)$;

bar $(4)$;

$\}$

static void foo$($int a$)\{$

system.out. print$($a$)$;

$\frac{?}{\text{b}\text{a}\text{r}}(a+1)$;

$\}.$

static void bar$($int a$)\{$

System. out.print$($a$)$;

$\}$

$\}$