garbage collection

[gayatri ganesh]

Hi,
Can someon explain the answer to the problem ? I understood why we get a but c,d,e I am confused .........

class A {
private String name;
private A otherA;
public A(String name) {this.name = name;}
public void other(A otherA) {this.otherA = otherA;}
public A other() {return otherA;}
public String toString() {return name;}
protected void finalize() {System.out.print(name);}
}
class B {
public static void m1() {
A a1 = new A("A1"), a2 = new A("A2"), a3 = new A("A3"), a0 = a3;
a1.other(a2); a2.other(a3); a3.other(a1);
for(int i = 0; i<4; i++){System.out.print(a0 = a0.other());}
}
public static void main(String[] args) {m1(); System.gc();}
}

Which of the following could be a result of attempting to compile and run the program?
a. A1A2A3A1
b. A0A0A0A0A1A2A3
c. A1A2A3A1A2A3
d. A1A2A3A1A1A2A3
e. A1A2A3A1A3A2A1
f. A0A1A2A3A1A2A3

Answers a,c,d,e

Thank you

[Mike Gershman]

Recall that an object is eligible for garbage collection when it can't be reached from an active thread.

Once method m1() has returned to method main(), local reference variables a0, a1, a2, and a3 are gone. While the objects refer to each other, they can't be reached from main(). Since garbage collection of each eligible object may or may not happen, all four possible answers are correct.