Does Garbage Collection Guarantee that a Program will not Run Out of Memory?

The work of Garbage collection in Java is to automate the process of deleting memory that’s no longer in use. But does that mean Java programs are free from memory limit overflow? Well in this article we will discuss it in brief, but first, let’s talk about the garbage collection in Java.

Garbage Collection:

In C/C++, a programmer is responsible for both the creation and destruction of objects. Usually, programmer neglects the destruction of useless objects. Due to this negligence, at a certain point, sufficient memory may not be available to create new objects, and the entire program will terminate abnormally, causing OutOfMemoryErrors.

But in Java, programmers do not need to care for all those objects which are no longer in use. Garbage collector destroys these objects. The main objective of Garbage Collector is to free heap memory by destroying unreachable objects. The garbage collector is the best example of the Daemon thread as it is always running in the background. 

But does garbage collection guarantee that the program will not run out of memory? Well, to know the answer to this question we must know about the working of garbage collection in Java first.

How Does Garbage Collection in Java Work?

Java garbage collection is an automatic process. Automatic garbage collection is the process of looking at heap memory, identifying which objects are in use and which are not, and deleting the unused objects.
An in-use object, or a referenced object, means that some part of your program still maintains a pointer to that object. An unused or unreferenced object is no longer referenced by any part of your program.
So the memory used by an unreferenced object can be reclaimed. The programmer does not need to mark objects to be deleted explicitly. The garbage collection implementation lives in the JVM. 

Does Garbage Collection Guarantee that Program will not run out of Memory?

The Answer is “NO“, Garbage Collection doesn’t guarantee that a program will not run out of memory. The purpose of garbage collection, as mentioned above, is to identify and discard objects that are no longer needed so that their resources can be reused.

Whenever there is insufficient space available for new object , garbage collection will attempt to reclaim memory by releasing memory used by objects which are not referenced in program.

But sometimes it may be possible that developer mistakenly creates objects which never go out of scope. Thus consuming more memory until all heap is exhausted.

It is the programmer’s responsibility to ensure that objects no longer in use are no longer referenced. That way the garbage collector can do its job and reclaim memory used by these objects.

What could be possible ways when our program run out of memory in Java?

• It might be possible that programs to use up memory resources are faster than they are garbage collected in memory.
• It is also possible to create objects that are not subject to garbage collection.
• It is also possible for a programmer to mistakenly create objects which never go out of scope.

Conclusion:

So after discussing about the working of garbage collection and possibility of memory usage we can say it is not guaranteed that a program in java will never run out of memory while using garbage collection.