How do Immutable Objects help decrease overhead due to Garbage Collection?

Question

I am a newb, and I have read about Garbage Collection from the first two answers here.

Now justifying the use of Immutable Objects even if the programmer has to create n

Answer 1

Immutable objects do not need a defensive copy if you are sharing them across contexts (.e.g calling code you don't trust) or for thread safety. This can mean that reads of immutable objects can be lower in terms of garbage.

On the other hand, every time you change an immutable object, you have to create new objects whether this is required or not. In this regard, immutable objects can create far more garbage.

The real question is whether you are making lots of reads, or lots of writes (or a mix) Depending on usage Immutable objects can save objects or create more objects, so it makes sense to use either Immutable or Mutable object based on your specific use case.

Note: most of the time, correctness is far, far more important than performance, and while in general Immutable objects have higher overhead IMHO, it is far easier to prove the correctness of data models using Immutable objects, and it is worth using immutable objects for clarity and ease of reasoning alone.