If
a program holds a reference to a heap memory that is not used during
the rest of its life, it is considered a memory leak because the
memory could have been freed and reused. A memory leak occurs when a
computer program incorrectly manages memory allocations.
Garbage collector won't reclaim the memory due to the reference being held by
the program. A Java program may run out of memory due to memory
leaks.
import java.util.*; public class ProcessRequest { static Vector<Integer> myVector = new Vector(); static void processReq(int iter, int num){ for(int j=0; j<iter; j++){ /* Simply Adding the request */ for(int i=0; i<num; i++){ myVector.add(i); } /* Remove the requests */ for(int i = num-1; i>0; i--){ myVector.removeElementAt(i); } //System.out.println(myVector.size()); } } public static void main(String args[]){ while(true){ processReq(1000, 5); } } }
Above
program simply add and removes elements from myVector. When you
closely observe the program
/*
Remove the requests */
for(int
i = num-1; i>0; i--){
myVector.removeElementAt(i);
}
There
is a problem in the above loop. Actually we are not removing all the
elements. The condition in the loop should be i>=0, but it is i>0.
So for every iteration, one object is not getting removed. I.e, for
Every iteration of the outer loop, one unused object is being added
to heap. Even though it is unused, JVM can't help you, since, JVM de
allocates memory of an object, if there is no reference count to this
object.
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