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In the last lesson in that the more we have seen that we can run into issues during the D.C. legalization

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process.

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So there is something more we need to know about D.C. validation process and that's something that we

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will see in this lesson we will also see how we can avoid the issue that we ran into during that Emel

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And here's the DC that can process.

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So we first read the serialized object and in the process GBM also tries to lower the corresponding

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class object.

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The class name of the serialized object will be stored with the serialized object itself.

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And so JVM looks at the class name and will try to load the corresponding class know D.C. delegation

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will fail.

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If for some reason the class cannot be loaded it could be because the GBM could not find the class file

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.

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Or it could be due to some other reason to.

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But if the class could be loaded successfully then as a second step GBM tries to compare the motion

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of the loaded class but the notion of the serialized object and the need to match a device it means

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that the class has evolved after the object was serialized and they are no longer compatible and due

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to this JVM with an exception NDC realization will fail.

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And this is what happened during the demo when the last lesson but if there is no motion mismatch then

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GBM would create space in the heap for the serialized object and recreate the object with the same state

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.

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So it's going to run that can strip it off the object because if that is done then it means that we

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are creating a brand new object that by Newsted and that is not what we want what we want is to recreate

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the object with the same state that the object had when it was serialized But if there is any norms

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Serializable ancestor in the inheritance tree of the serialized object then that ancestors construct

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it would be done along with any constrictors of all it's direct or indirect superclasses under super

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process maybe Serializable do.

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And that wouldn't matter so conceptus would run starting with the first Nahm Serializable ancestor unbe

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already know this as part of restoring state.

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Instance variables will get serialized did while Crunchie and variables will get default values so that's

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a B.S. legalization process.

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Let's not look at more specifics about worshipping every Serializable class gets a version ID which

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is computed from the classic structure on this motion ID is stored with that dot Busfield know it and

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the plastic took genius the Russian idea also genius on this motion ID has a name under the name Das

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serial quotient you ID as an idol of this Light That Is it as a bush an ID of a serializable class.

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So sort of wish an ID is specific to only Serializable classes on Hence we have the term CDO in the

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name of the ocean ID.

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So this motion ID will not be gender dered for non-C realisable process know in a seat an object is

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generated then the object is time.

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But the motion IAB that the class had in that instance of by and during B.C.E. realization I spark off

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Worsham comparison devotionally of serialized object will be compared with the Russian idea of downloaded

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to us so if the class has evolved after the object was serialized then obviously motion ideas were mismatch

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.

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Transition.

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And this is what happened in the last Dynel So the question would be how can we make D.C. realization

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to succeed even when the class has a world after serialization and the solution is to make the version

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ID constant even if Grassley wants NBC how that can be done.

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Let's get back to our demo cook here we are in the I will do more class once again and we're going to

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continue with where we left off.

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So in the last day more we made this change uncommented gender.

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So the class has evolved unbid that we had a version mismatch NDC realization has failed and we just

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mentioned that in order to resolve that we need to keep the and the constant so that can be done by

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declaring a constant CDL Worsham new ID as you can see here since it needs to be a constant.

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It has marked dust not big on final and it has to be long.

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On here as a senior Beauchesne you ID and we are using the name as it is.

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And it is assigned this value.

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And the question is can we get this value from on for that Java library comes with a tool called Silver

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.

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OK.

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And we are going to use that silver and we are going to pass.

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We are going to run that tool and we are going to pass this in can be passed on in the movie then we

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get done serial version of this particular class.

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So in order to do that let's just go back and start from the beginning.

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So let's just call this art and just keep this as it is me open my command prompt here.

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So I am and gee I read them all.

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So there is the current project and I'm in the bin folder because in the bin for dinner itself we have

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the classifiers OKB in the demo we how both SIRC unbent and within the bin.

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We have the actual classifiers.

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So we need to go into the bin folder.

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Let me just run this command.

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So it's called Silver and we are running it on the Iodo more dollars Serializable Demel because you

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didn't as a builder I was a nested class.

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We can access it this way.

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This silver is being is it is being run on that docked classified.

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So if you look into this folder I will falter here you will see I will do a moderate class as well as

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as well as I order more dollars Serializable Demel and you will see both of them.

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So we are running the seedier version on this particular Serializable nested class because we want that

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serial quotient ID.

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So on this if we run it.

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So this is what we get and it's already here.

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So it's just the same number.

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So I'm just going to uncomment this.

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Now let's just go ahead and say Run.

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Run configuration.

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Recall that we need to pass through here in order to serialize the object.

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So we are going to start from the beginning and I'll say apply here and run it and I go back there more

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and if I hit refresh it will see dark.

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That is the CD a lot easier.

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OK so Dr. template has done seat on this object now.

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I mean just go back so let's not involve the class so let's just do this Bartletts not regenerate there's

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not that research realize that blasts so let's go back and do it on configurations into arguments maybe

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modus So with this only desalinisation Isbel form and now you can see that despite uncommon doing this

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we did not get the exception that we had earlier.

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OK.

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And that's because we how hard coded the Russian ID.

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So even so the object serialized object has had this notion ID but the class has evolved and we hardcoded

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the ocean ID.

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So when we run as a serial version let's run it once again so with this is with no change and you will

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see that it still has the same bush an ID.

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OK.

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So we are hardwiring the Russian idea here.

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So that's how you can ensure that because your position does not fit.

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But there are some changes and if you make those changes.

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Utilization still fit.

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For instance let's do this let's just make it NC realisable OK.

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No actually if you run version ID it will not be when See it says that it is not serializable because

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in order to because there is no emotion or devotion I doubt you will be generated only for Serializable

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classes.

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Q So the old version but also say that it cannot.

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It cannot.

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It cannot give us any question Id.

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Now that's just go ahead and run this.

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So with this change we will once again get this error which means that ABC Television has it.

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So there are certain changes that we can make on certain changes that we can not make.

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OK.

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So let's head over to our site and see what changes we can make and what we can not make.

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OK.

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And this class as available and the resources section on you can check it out on download on book critic

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so let's just go back to our sleights

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unhidden the changes that do not affect D.C. realization on most of these are about instance variables

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you can add or delete an instance variable to the class and that will not break.

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Between the audition process if you add an instance variable it will get the default value.

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You can also make an instance variable static you can change a transient variable and go nonconstant

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and the variable would still get the default value good NBC television you can also change access levels

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off the tables and duckbill don't have any effect.

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Finally you can all add classes to the inheritance tree and you can also REMAUT classes from the inheritance

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tree and that wouldn't affect the D.C. delegation process.

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And these are a couple of changes that do affect DC that position you cannot change the data type of

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an instance variable.

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We have to see the second one in our demo.

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That is you cannot make a CD and as a bluegrass non-C then visible but this rule is not for just the

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class itself but if the class includes one or more object graphs then none of the Serializable classes

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that dingo's object graphs can be made on Serializable So even if one class is made Nancy Serializable

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within an object graph then it would break the DCD tradition process.

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So that's about it.

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I would also suggest that you should try out all these genius in code and see the results for yourself

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.

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So to summarize serialization is useful for saving regular Java objects to devices like desk to recreate

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Java objects from their serialized form people from DC theorization and B use object output stream an

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object input stream process four-CD elevation NBC idealisation finally if you want the classes to evolve

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without affecting DC or they can then you can define a constant Silverbush an ID.

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But you need to bear in mind that DCR addition can still fail with certain genius so that's about it

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.

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Hope you enjoy learning about serialization.

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And thank you