Often, when we develop applications, we have to transfer data from one Activity to another. Of course, we can not do that directly. The data we want to transfer must be included into a corresponding Intent object. And if we want to move a complex POJO (e.x. Person, Car, Employee, etc.) we also need to perform some additional actions to make that object suitable for a transfer. To do that, our object must be either Serializable or Parcelable.