Question

I was going through the online tutorial provided by oracle. One of the exercises has a question as follows:

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The following code creates one array and one string object. How many references to those objects exist after the code executes? Is either object eligible for garbage collection?

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String[] students = new String[10];
String studentName = "Peter Smith";
students[0] = studentName;
studentName = null;
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Answer: There is one reference to the students array and that array has one reference to the string Peter Smith. Neither object is eligible for garbage collection.

(http://docs.oracle.com/javase/tutorial/java/javaOO/QandE/objects-answers.html)

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Surely the last line means studentName is eligible for GC? Really confused, and I think this means I have not understood the nature of “null” and also object referencing properly, which is why I ask.

Answer 1

Before assigning null to studentName there are two references to “Peter Smith” (studentName and students[0]). After null is assigned to studentName, “Peter Smith” is still referenced by students[0]