Java - What is the output of this code?

class A {

private static int j;

private int i;

public A() { i = j++; }

public void someMethod() { System.out.print(i + " "); }

}

A a1 = new A();

A a2 = new A();

a1.someMethod();

a2.someMethod();

...

a) 0 1

b) 1 2

c) Runtime Error

d) Compilation Error