Are there additional memory costs for Integer objects compared to using primitive int? If yes, what are they?

Yes, Integer objects occupy more memory compared to the primitive int. The primitive int is just 4 bytes storing the numeric value. An Integer object, besides the value itself, contains metadata such as the object header, a reference to the class, etc. In the JVM, this typically adds several dozen bytes (depending on the implementation and architecture). Additionally, objects are created on the heap, which requires extra memory for management and garbage collection.

It can be roughly estimated that an Integer takes 3-4 times more memory than an int.