RE: Beginner java question: Serializable

["Lim Hock-Chai" <Lim.Hock-Chai@xxxxxxxxxxxxxxx>]

Implement Serializable for remote processing makes sense for me.  Tomcat's 
complain about my java bean is not Serializable threw me off a bit and got me 
thinking if I need to implement it on my java bean.  

I'm still learning java and web programming.  Currently trying to create a 
shopping cart web app just to get my feet wet in these areas (need to brush up 
my html though.  The screen looks ugly than a green screen. lol).  From your 
responds, I don't think I need to implement Serializable yet.  Unless, I want 
to create a very sophiscated one that like you mentioned.

thanks for everybody's respond.





-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx
[mailto:java400-l-bounces@xxxxxxxxxxxx]On Behalf Of Ivan Hurtado
Sent: Monday, December 20, 2004 12:15 PM
To: Java Programming on and around the iSeries / AS400
Subject: RE: Beginner java question: Serializable


As long as that particular session is active you are
correct that you do not need to serialize anything
because you have your data stored as objects in the
session scope. But what happens if the user walks away
for lunch and his session times out? You would hope
that the last state of the user's session was somehow
saved in order to start him back up where he left off.
The two commonly used methods to do this are to either
store the data in a database, or to serialize the data
just prior to the session being invalidated. Then when
the user logs back on, your app can restore the data
from one of those.

Obviously, you're not going to serialize every
instance of a serializable class... only when you need
to. But in order to do so, you have to declare your
class as implementing the Serializable interface, or
as a sublass of something else that does so.

FYI - As mentioned previously, serializable has been
used for remote processing across separate JVMs, and
is  also used on occasion to clone objects. Cloning
objects in java can be a bit cumbersome sometimes,
especially with user defined objects. Serializable
allows for a quick & easy save/restore mechanism.

One word of caution though... serialized objects are a
potential security hole for hackers. Once the data is
serialized, it can be tampered with. So be careful
where you place it. 

Thanks,
Ivan Hurtado