I’ve recently had a discussion about the way lists and other data structures are stored in memory, especially when it comes to references and their assignment. It turned out that deep and shallow copy raise questions, which for someone who comes from a C++ background (such as myself), have quite obvious answers. Before I switched to Java, I had to think whether I can safely iterate over a data structure created by a different object or I had to duplicate a part of it in the memory, before it gets swiped by the original owner. Java makes it less explicit what sort of memory ownership You have, therefore today I’d like to look under the hood to give You a simple, yet powerful understanding of the differences between an UnmodifibleList, ImmutableList and finally a thorough copy of it. Let’s dive in!

On each git pull I get more and more branches created locally, because they appeared on the remote. Also, I end up with my own, already merged and the list just keeps growing.