Can anyone tell me why bundles are serialisable ?

Bundle is Parcelable

Parcel is the protocol "someone" decided on for prosesses to talk together in Android. But you are asking "why", have you googled it? It is better that you ask a more specific question if something is unclear. https://stackoverflow.com/help/how-to-ask

@ahulyk I understand they are parcelables that's why they are serialised but do you any insight why they are made like that. Because while communicating with two activities why we need Bundles as serialised ?

@Saket Poddar please google more on this -> The IPC communication in the Android framework is based upon the concept of 

Binder

. Main mechanism to allow data marshalling between those processes is based on 

Parcel