Garbage Collection

[ishani sharma]

hi,
I was reading through and found that in following codes

#1

public class Island {
Island i;
public static void main(String [] args) {
Island i2 = new Island();
Island i3 = new Island();
Island i4 = new Island();
// (1) 
}
}

At (1) 3 objects are eligible for garbage collection.


#2

public class Island {
Island i;
public static void main(String [] args) {
Island i2 = new Island();
Island i3 = new Island();
Island i4 = new Island();
i2.i = i3; // i2 refers to i3
i3.i = i4; // i3 refers to i4
i4.i = i2; // i4 refers to i2
i2 = null;
i3 = null;
// (2) 
}
}

At (2) 4 objects are eligible for garbage collection


#3

public class Island {
Island i;
public static void main(String [] args) {
Island i2 = new Island();
Island i3 = new Island();
Island i4 = new Island();
i2.i = i3; 
i3.i = i4; 
i4.i = i2; 
i2 = null;
i3 = null;
i4 = null;
// (3)
}
}
At (3)  3 objects are eligible  which are i2, i3, i4 and the objects i2.i, i3.i, i4.i are not eligible

Please tell me whether i am right and where i am right and where i am going wrong??

[Joanne Neal]

ishani sharma wrote:At (1) 3 objects are eligible for garbage collection.

No. You are still in the main method, so no objects are eligible for GC

ishani sharma wrote:At (2) 4 objects are eligible for garbage collection

As you only create 3 objects, that's highly unlikely.

ishani sharma wrote:At (3) 3 objects are eligible which are i2, i3, i4 and the objects i2.i, i3.i, i4.i are not eligible

Again, you are only creating 3 objects.

i2, i3, i4, i2.i, i3.i and i4 are object references. These are never garbage collected - only objects are garbage collected. Object references refer to objects and you can have several references referring to a single object. You need to work out which references refer to which objects and then once you've done this, if there is an object with no references, it will be eligible for GC.

[Hama Kamal]

At (1) 3 objects are eligible for garbage collection.

At (1) in the main scope no objects are eligible for GC , however when main method completes threee objects are eligible for garbage collection

At (2) 4 objects are eligible for garbage collection

At(2) no objects are eligible for GC.

At (3) 3 objects are eligible which are i2, i3, i4 and the objects i2.i, i3.i, i4.i are not eligible

At(3) three(3) objects are eligible for GC.

[ishani sharma]

check this thread

Henry Wong wrote

Four objects -- two Icelandic objects (created at line 11 and line 13) and the two Long objects contained in those two Icelandic objects.

Is what he said is wrong?? which objects are eligible at 15. ??

[Hama Kamal]

ishani sharma wrote:check this thread

Henry Wong wrote

Four objects -- two Icelandic objects (created at line 11 and line 13) and the two Long objects contained in those two Icelandic objects.

Is what he said is wrong?? which objects are eligible at 15. ??

what he said is perfectly right ..

[ishani sharma]

Hama can you please explain how 2 Long objects alongwith objects created at 11 and 13 are eligible??

[Hama Kamal]

ishani sharma wrote:Hama can you please explain how 2 Long objects alongwith objects created at 11 and 13 are eligible??

through inheritance each object on line 11 and 13 contains( Long weight) when the objects on line 11 and 13 become inreachable the Long objects become inreachable as well.