Garbage Collection

[Roman Mazur]

package testscjp;
interface Animal {
    void makeNoise();
}
class Dog implements Animal {
    Long weight = 20L;
    public void makeNoise() {
        System.out.println("dog");
    }
}
public class Main4 extends Dog {
    public void makeNoise() {
        System.out.println("main4");
    }
    public static void main(String[] args) {
        Main4 m1 = new Main4();
        Main4 m2 = new Main4();
        Main4 m3 = new Main4();
        m3 = m2;
        m1 = m2;
        m2 = null;
        m3 = m1;
    }//line x
}

How many objects are eligible for garbage collection in //line x?
I think there are three objects but I ‘m not sure about “weight” object in Dog class.
Can some one confirm the number?

Thank You
Roman

[Punit Singh]

I think 4 objects are eligible.

m1 ---------> 1st main4 and weight
m2 ---------> 2nd main4 and weight
m3 ---------> 3rd main4 and weight

m3 = m2;
m2,m3 -----> 2nd main4 and weight
xxxxxxxxxxxx 3rd main4 and weight eligible for gc

m1 = m2;
m1,m3,m2----->2nd main4 and weight
xxxxxxxx 1st main4 and weight eligible

m2 = null;
m1,m3 ----> 2nd main4 and weight

m3 = m1;
m1,m3 ----> 2nd main4 and weight

so total 4 object 1st and 3rd main4 with their weights.

[Roman Mazur]

Thanks Punit,
this is a good explanation.

Roman

[Ankur kothari]

[jayalakshmi charugundla]

Want to know punit explanation is correct ?

Because kothari you didn't say anything?

[Punit Singh]

Kothari is jumping, so may be my explanation could be correct

[Gustavo Guanilo]

is a very clear explanation I was a little confused with GC .. I am very grateful

[Ankur kothari]

best explanation of gc ever seen by me

[Jack Bento]

Why does weight count as an object? I thought it was just an inherited member?

[Ankur kothari]

dude its an inherited member that refers to an object......

[Jack Bento]

but weight is a primitive type Long. What object does that refer to?

[Ankur kothari]

Long is a wrapper which is object not a primitive

[Jack Bento]

Ah so if it had

int weight = 20; 

then the answer would be 2 objects.

Thank you Ankur for pointing that out to me