new object in method

[Chris Palau]

Hello,

I am reading the SCJP 6.0 Certification book from Kerry and Kathy and I have a doubt I can't clarify with the book info. I googled but I didn't found any info about that. My question is about the JVM garbage collector.

For example, if I have a method like this:

public void getData() {

StringBuilder sb = new StringBuilder();

}

The book explains this: "local variables are in the stack and instance variables / objects in the heap. When a method finalizes and returns: local variables are eligible for garbage collection", but my question is: what about the object instantiated in the method ? Is automatically eligible for garbage collection also ?

if I have the same example but in a for statement like this:

for (int i=0; i <1000; i++) {
StringBuilder sb = new StringBuilder();
}

StringBuilder object is elegible for garbage collection when the for loop finish ?

Thanks
Chris

[Omar Al Kababji]

Yes

[Nitesh Kant]

Not a performance question. Moving to SCJP certification forum.
Please CarefullyChooseOneForum while posting.

[Rajshekhar Paul]

Objects created with local variables are always eligible for garbage collection unless the reference to that object is passed outside the scope of that variable.

public String getAString() { 
String s = new String();
return s;
} 

In the above case, the scope of s is the method body only. But as this method returns the object reference in a return statement, the object will not eligible for
GC after the execution comes out of the method body.

public void printAString() { 
String s = new String();
System.out.println(s);
} 

But in the above code, the object refernced by s will be eligible for GC once the execution comes out of the method body as this object is not referenced furthur.

Hope this helps.

[RaviNada Kiran]

Thank You Very Much Rajsekhar it is really valuable for me

[Abhi vijay]

I had seen a question in Devaks's Simulator. dont remember the number.

It was adding an object into a collection(Vector), so its not eleigible for GC. But what if this collection is declared inside a method?

[Punit Singh]

then collection object itself is eligible for gc after the end of that method.