Re: serialver?

From:

Lew <lew@nowhere.com>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 02 Dec 2006 02:38:01 -0500

Message-ID:

<QsednbfQlOLHsOzYnZ2dnUVZ_sCdnZ2d@comcast.com>

EJP wrote:

CapCity wrote:

You need to run serialver from the directory which contains the topmost
package, or you can specify the classpath on the command line.

Also, do I need to generate a new one everytime the class changes?

On the contrary, you should *never* change it. If you introduce
serialization incompatibilities you should use one of the various
mechanisms available so that the readObject() method will understand
serializations from older versions of the class.

Joshua Bloch in _Effective Java_, Item 55, "Consider Using a Custom Serialized
Form":

"If you ever want to make a new version of the class that is /incompatible/
with existing versions, merely change the [serialVersionUID] value in the
declaration. This will cause attempts to deserialize serialized instances of
previous versions to fail with an InvalidClassException."

A class will be incompatible with earlier versions if you added or removed
serializable (non-transient) members.

Never say never.

- Lew