Why do we need hashCode, equals ? In most if the cases we never use it.

useful when you need to compare objects

@suhas That’s okay. So most of the case we never use hashCode and equals. So choosing

data class

over

class

will be overhead right ? class also generates setters and getters

but data class generates a toString, which might be useful unless you want your toString to be json output

@Nikky I don’t think

Gson

uses that

toString

from

data class

. Only use of

toString

is logging

exactly

@Nikky But that will be only helpful during debugging

you can't really know if those are never used. your app is very likely to contain at least one place where Object.equals() or Object.hashCode() is called. statically checking whether that code could be dealing with an instance of your data class at runtime is very expensive to impossible

@cketti I got the thing regarding proguard. But then it will be recommended to use

class

as model as compared to

data class

Did you measure if the overhead actually affects you? I mean if you want no overhead for the sake of no overhead, follow the tutorial on writing your app in assembly which recently popped up on Reddit ;-)

@Paul Woitaschek I have already mentioned about unnecessary size of class

hashCode is used for storing objects in HashMap and pretty much every Collection starting with Hash.