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Hi there.

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Now let's look at the lifetime offer pipe which means that we are going to look at what happens to your

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type since the time it does access for the very first time and the time it is executed and how it can

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be either a class or an interface.

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But when you look at the lifetime R-Type let's look at what components of JVM we are going to discuss

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in this chapter.

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You may recall this illustration from our first chapter when discussing JVM.

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So here we have a class called Halo which needs to be executed by Gibeon.

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And in this chapter when discussing the lifetime of type we will discuss these two components classloader

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on bytecode verifier.

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And once we are done with lifetime type we will look at garbage collector and to an extent we will also

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look at bytecode instructions on Witan the execution engine.

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We only did this because the G.I. decompiler in first chapter while discussing JVM and I think that

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discussion would suffice and if needed to support TLAs separate lesson object decompiler at some point

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in the future.

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But the discussion we had should suffice.

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Now at the top we have the different runtime data areas which represent the memory that GBM is a look

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at it.

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So when GBM get started it gets a look at it a chunk of memory from the underlying operating system

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on GBM splits that memory in two different areas which we can see here and we would be discussing most

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of these some areas.

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So that's got to be a micro texture.

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Now let's look at life in a market like let's consider this class called us Halo and let's assume that

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this class is being accessed for the very first time which means that it is either being run from the

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command line or it is being accessed in some way from some other place.

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That is we are either creating an instance of this class or accessing some variables hard matter within

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this particular class.

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But this class is being accessed for the very first time and in that case we need to load this class

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into memory and JVM does that sort of holds the class and it checks that this class is well-formed or

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not.

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That is whether it is obeying the language introduced off giallo.

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Now we know that that is already done by compiler.

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Hello dark glasses generator.

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So the question is why is it doing.

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One more time.

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And the reason is this glass hollowed out glass could have been downloaded from across the network and

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it could have been compiled by a hostile compiler whose intention is to perform some malicious actions

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on the system on which it is going to be executed.

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So JVM is not going to trust any of the classes that are just going to execute.

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It needs to perform this kind of a check and if it finds that it is not real fun it is going to reject

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this class which means that it's not going to exhibit it.

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But if the fight is well formed then it.

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Look it's best for any of the static variables within this class undergrad also going to initialize

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those variables but the default values which is dependent on the data type of the variables.

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None of this Grothus access for the very first time by creating an instance of it.

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Then on the instance variables will also be looked at that space and they would be initialized with

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default values.

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So the next step is to look at any reference classes.

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No Hello non-class might be referencing other classes.

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That is it could be accessing variables or methods in other classes or it could be creating instances

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of other classes.

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So in this case we are going to at all the classes that are being referenced from the US and the final

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step is to initialize variables.

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Earlier we created a space for static variables and we initialized them with different values.

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So here we are going to override those default values with the actual user defined initial values which

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are part of either the Declaration or they could be part of the static initializer gawks or instance

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initializer groks.

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So those are the different steps.

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And this first step where we are loading class it is called us loading underdosed performed by this

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component called us classloader.

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So when classloader has to load this class called Hello Doc class it's just a class bot to see where

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it can find this class and once it finds that class once it gets it it reports a corresponding byte

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course into memory.

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And after that it generates something called as a class object which is the output of the loading step

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on class object simply has the Mattei information about this class.

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So that information would be things like the class name which is hollow and names of any of the superclasses

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and it would also include information like method names and so on.

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We very briefly discuss the class object while discussing the object class in the okes chapter not duck

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discuss object will be created only once when the corresponding class is accessed for the first time

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.

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So on subsequent accesses classloader will simply fits to create a class object from the memory and

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it would use it.

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So the output of this loading step is a class object and that would be the input for the next step.

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It is linking unlinking has these three steps which are represented in this three boxes on the first

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step is cardless verification.

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Because we are simply verifying whether the input class is well-formed or not on verification as performed

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by a component called bytecode verifier and the next step is called preparation and the third step is

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called a resolution because we are resolving the referenced classes.

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Note that here the classes are being loaded at runtime.

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OK in a dynamic range.

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Undo to that.

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This kind of linking is called as dynamic linking because it is happening dynamically at runtime.

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Now in some languages there is also static blinking which happens at compile time itself so it does

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not happen at runtime so the referenced process will be copied into the final executable at compile

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time itself on this resolution step is an optional step which means that it can happen right after the

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preparation step.

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Or it can happen after the next stage which is initialization where we're actually initializing redeemers

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so it can also happen after initialization stage.

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So the third step is the initialization step under simply initializes the variables.

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As discussed earlier.

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So overloaded the default values that the user define any shell about use.

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So those are the three stages loading linking and initialization.

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No not that when we are loading a glass it's superclasses will be loaded before the current class so

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its superclasses can be loaded uninitialized before the current class.

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OK so the superclass of hello will be loaded and initialized before hello.

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As noted on wanting to know about initialization is dark and this gives the pipe as a class but if pipe

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happens to be an interface then it will be loaded but not initialized under could be initialized only

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if one off its tactic methods are accessed and we know that in interface's topic methods are possible

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only from Jawa 8 onwards before July 8.

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Interfaces cannot how static methods.

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So that's one way in which an interface gets initialized and the second way is if it is accessed in

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an interface but the field is initialized via a method.

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In that case initialization is possible.

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So that's about initialization.

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With respect to interfaces on Finally the type will be executed.

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So if you are accessing a particular matter then that particular matter in the class will be executed

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.

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So those are the three stages.

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Loading linking on initialization under a high level overview of these stages are in the form of lessons

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we are going to get into the details of loading and linking unfought initialization.

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There is nothing more to discuss with regards to initialization of interfaces.

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We are going to look at that in a very detailed way in a demo which we will be doing after looking at

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the theory part of the lifetime of a type.

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So once we are done with the theory part of the lifetime of our type we are going to do more detail

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more of the total lifetime type and that's when we will also look at the initialization of interfaces

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and that's about it.

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Thank you