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q on garbage collection

JayaSiji Gopal
Ranch Hand

Joined: Sep 27, 2004
Posts: 303
From the following code how many objects are eligible for garbage collection?
String string1 = "Test";
String string2 = "Today";
string1 = null;
string1 = string2;

A) 1
B) 2
C) 3
D) 0

I answered 0 but the correct answer is one.
I answered 0, bcos string1 is set to null, but in the very next line, is says string1 = string2.

plz explain.

SCJP 1.4, SCWCD 1.4<br /> <br />Thanks in advance!<br />Jayashree.
Barry Gaunt
Ranch Hand

Joined: Aug 03, 2002
Posts: 7729
Jayashree, please quote the exact source of these questions. This one is clearly wrong.

Ask a Meaningful Question and HowToAskQuestionsOnJavaRanch
Getting someone to think and try something out is much more useful than just telling them the answer.
John Neel

Joined: Jul 20, 2004
Posts: 6
i feel the answer 1 is correct.

as the object "Test" is not referred by any one, it can be garbage collected.

plz correct me if i were wrong
sandu sudhakar

Joined: Nov 17, 2004
Posts: 4
Ref: article

"String Literals are not eligible for garbage collection".

So in this example, none of the objects are eligible for garbage collection.
Answer: 0
Mike Gershman
Ranch Hand

Joined: Mar 13, 2004
Posts: 1272
From Bert Bates (who should know):
focus on non-String objects when you're studying GC, don't worry about GC and Strings together.

This is a problem with some mock exams, they have clever questions that are outside the exact scope of the exam.

Mike Gershman
SCJP 1.4, SCWCD in process
It is sorta covered in the JavaRanch Style Guide.
subject: q on garbage collection