Help with serialization

[Christo]

as part of a project at uni i have been asked to provide object persistance
through files

I have opted for serialization

my question is quite simple

when u use serialization is an object saved to a single file or are more
than one object(s) saved to a single file?

say i have three objects, will they all be saved into one file or will there
be three seperate files each having one object saved into them?

also say i have a superclass implmenting the java.io.Serializable

will all subclasses of that superclass automatically implement the
java.io.Serializable or will i need to make those subclasses implement the
Serializable seperately?

any help would be appreciated

PS -
public class UserData implements java.io.Serializablei understand that
but..public class UserData extends User...how would i implement the
java.io.Serializable in that class? would it be...public class UserData
implements java.io.Serializable extends UserORpublic class UserData extends
User implements java.io.SerializableThanks in advanceChristo

[Eric A. Maginniss]

Christo wrote:

as part of a project at uni i have been asked to provide object persistance
through files

I have opted for serialization

my question is quite simple

when u use serialization is an object saved to a single file or are more
than one object(s) saved to a single file?

say i have three objects, will they all be saved into one file or will there
be three seperate files each having one object saved into them?

also say i have a superclass implmenting the java.io.Serializable

will all subclasses of that superclass automatically implement the
java.io.Serializable or will i need to make those subclasses implement the
Serializable seperately?

any help would be appreciated

PS -
public class UserData implements java.io.Serializablei understand that
but..public class UserData extends User...how would i implement the
java.io.Serializable in that class? would it be...public class UserData
implements java.io.Serializable extends UserORpublic class UserData extends
User implements java.io.SerializableThanks in advanceChristo

Serialization is about converting objects into Streams of
reconstitutable data. What you do with the stream is up to you. Also,
once a class implements an interface all subclasses automatically
implement it.

Java API Javadocs are your friend:
http://java.sun.com/j2se/1.4.2/docs/...putStream.html

Another thing to look up is the java keyword "transient"