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The serializable class does not declare a static final serialVersionUID field

Siegfried Heintze
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Joined: Aug 11, 2000
Posts: 381
What the heck is eclipse 3.2 talking about when it gives me the following warning:

"The serializable class XYZ does not declare a static final serialVersionUID field of type long"

Eclipse will generate such a field for me. I'm just creating a descendant of class Applet.

thanks,
siegfried
Ernest Friedman-Hill
author and iconoclast
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Joined: Jul 08, 2003
Posts: 24183
    
  34

If you explicitly put such a field into a serializable class, then you can use it to provide versioning for serialized data files containing this class. Class versions with the same SerialVersionUID have compatible serialized data, by definition, even if the class changes.

But if this doesn't matter to you, then just ignore the warning.


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Bauke Scholtz
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Joined: Oct 08, 2006
Posts: 2458
For your information: in Eclipse you can change the importance of compile errors/warnings to your taste by Window - Preferences - Java - Compiler - Errors/Warnings. Specific this one can be found in the group called "Potential programming problems".
Robert Hill
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Joined: Feb 24, 2006
Posts: 94
Disabling it might cause trouble down the road. If you mean to serialize an object the warnings will help you remember.

You can keep the warning turned on and either ignore it or get it out of sight by placing this line above public class ... : @SuppressWarnings("serial")
Siegfried Heintze
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Joined: Aug 11, 2000
Posts: 381
Does someone have a favorite URL/tutorial that describes how one uses this unique value for versioning with serialization?

Thanks,
Siegfried
 
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