Serialization

[Prahalad Deshpande]

Hi Ranchers,
Does serialization work with inner classes? Meaning if I have a class say Outer and there is an inner class called Inner can then we use the writeObject and readObject methods on the outer class to serialize it? Or should we be implementing the serializable interface in the inner class as well?
I can post the sample code if anyone needs to have a peek at it

Thanks for the help in advance

Regards
Prahalad

[Kalpesh Jain]

I think (though not sure) that inner classes implicitly extends everything from outer class and acts like just another member of outer class. So if outer class implements Serialization, inner classes will also have the facility to get serialized.

[nivas ratthaaq]

I think inner class considered to be an member of outer class. So If you want to serialize outer class then inner class also must implement the serializable interface.

[Naveen Zed]

Inner class is also a class, so it must implement Serializable to be eligible for writig.

[Burkhard Hassel]

Kalpesh Jain posted November 14, 2006 01:35 PM

I think (though not sure) that inner classes implicitly extends everything from outer class.

That seems to be a common mistake. The inner class is totally independent from the outer regarding inheritance!


eg.

class Outer implements java.io.Serializable {
public static void main(String... args) {
Outer outer = new Outer();
Inner inner = outer.new Inner();
System.out.println(inner instanceof java.io.Serializable);
}
class Inner {}
}

prints false


and
System.out.println(inner instanceof Outer);
won't even compile.


Yours,
Bu.