The Dilemma is "what's the main difference...", but the most voted solutions reply with "as opposed to telling you what's the primary difference I'm telling you the way you need to work" stenci You'll be able to implement readonly key word, but in this way, You must initialize readonly fields https://whitelandgurugram.co.in/whiteland-westin-residences-gurgaon-redefining-ultra-luxury-living-in-sector-103/