I just came across "WTF" sort of error: I updated one of my classe's methods and added one method too. After running my program, this is what popped our when program tried to open and unserialize recently saved data (before the methods changes):
java.io.InvalidClassException: cz.autoclient.settings.Settings; local class incompatible: stream classdesc serialVersionUID = 2404650814140543454, local class serialVersionUID = 4256355437298300223
According to what java documentation says about that, java methods are not being serialized. So why does the serialVersionUID take class methods in account too?
Since Java programmers seem to be so mad about using getters and setters literally everywhere, why is it not possible to create getter for serialVersionUID so that I can implement my own algorithm that only calculates the properties?
The serialVersionUID can be overriden, but only with static final long serialVersionUID value which would require me to remember to change it when I change class's properties.
Based on the documentation for java, they recommend to use custom serialVersionUID as much as possible, because the default algorithm will take class implementation details and the result is said to vary from JVM implementation to another.
The default algorithm used by Java to generate the serialVersionUID seems to be considering the non-private methods (step 7) as well. Which explains the exception if you were using the default serialVersionUID in your implementation.
EDIT:
As you suggested, it would be great if we can have our own implementation of a method to do this, rather than overriding the serialVersionUID as a static final long. But I guess they don't allow that because if it were allowed, wrong implementations of such a method could invalidate the whole purpose of the serialVersionUID.