Write a sub class of Parcelable to another Parcel

class B implements Parcelable{
//lets assume you have A as a data member 

A obj;
public void writeToParcel(Parcel dest, int flags) {

        dest.writeParcelable(obj , flags);

    }
}

if you want to read it use this

 obj = in.readParcelable(A.class.getClassLoader());