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So that's the end of that.

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J.B. I'm in dentals chapter and Bonneau have a good understanding of the internal workings of the Jalla

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platform.

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Let's go ahead and review some of the main features we covered in this chapter.

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We began this chapter by looking at the lifetime of a type.

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We saw that a pipe goes through three stages from the time it is access for the very first time to the

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time it is executed.

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The three stages are loading linking and initialization learning is nothing but glassblowing and it

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is performed by the classloader which is a GBM component.

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When the glasses axis for the very first time the classloader searches for the dark classifier.

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And once it is found it will lower the corresponding bite caught the memory and will also create a class

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object for that particular class.

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So the output of this stage is a class object which will be in the next stage which is linking linking

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is a most complicated of the three stages and it involves three suffixes verification preparation and

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optional resolution step verification ensures that the classloader is safe to be executed by JVM.

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That is it ensures that it's not compiled by a malicious compiler next preparations don't create storage

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for that use an initialization with default values.

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Third step is resolution which is responsible for loading any grassers that the current class is accessing

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to be more specific as the bermed resolution suggests it resolves any symbolic references by replacing

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them with direct references.

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Example references could be two classes or any fields or methods in those classes.

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Also the resolution can be performed right after Operation step in which case it is called as early

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loading or it can be delayed to a later time in which case it is called lazy loading.

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Typically more DBMS implement lazy loading in which case classes are loaded only as they are and counted

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during the program execution.

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Finally we have the initialization stage in this stage.

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Static fields that were earlier assigned default values during the preparation step will be done with

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a user defined initial values.

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Next we look at the reflection reflection allows programs to do two things.

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One is it allows programs to introspect known or unknown code that would allow us to view Rockmart that

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feels an constrictors are defined in a particular class on a particular object.

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One example usage of this can be found in ideas like Eclipse which allow us to browse fields on methods

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in a class or an interface.

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Reflection also allows us to affect the runtime behavior.

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For example if you just know the class name at runtime you will be able to load the class create an

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instance of that class.

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And even in metrics on that instance and even set or get values of fields of that instance if you'll

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recall we discussed briefly about ambition processors and dynamic proxies both of these use reflection

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to affect the runtime behavior.

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Next we looked at the different runtime data areas that formed part of the Gibeah memory which is a

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look at it but the underlying operating system one of the runtime data areas is heape which is where

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all the objects are stored.

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Even arrays and class objects get stored here.

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Basically it is where we how all the instance data matter area is where we store plastic to between

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grid Mad-Eye information about classes and also the actual method bytecode.

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It would also include the runtime constant.

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Well not that priority of Java aid method is part of permanent generation space but from Java 8 onwards

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method is part of a news is called model space which is part of the of memory.

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So there is not firm space anymore but metal Elyon heap are shared across all threads and other runtime

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the diarrhea that we discussed in detail is a stock which holds information about the methods that are

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currently being executed for each exit getting murdered.

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We will have a corresponding stack frame on the stack.

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Recall that if a local variable in the method is an object reference then that reference will be stored

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on the stack frame itself.

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But the actual object it is referring to will still be on the heap.

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OK.

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So just keep that in mind now as you can see here the GBM stack native stack and the program counter

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are maintained at a partridge level.

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Finally native heape is basically the total user space minus a Java heaps.

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Ms.

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How are some of the runtime data areas like the metro area the stacks under PC icon for some of the

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space so near to memory is basically the leftover part that you can see here on the left corner of the

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diagram.

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Next we'll have that automatic memory management which is one of the main benefits of Java over a language

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like C++.

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It helps in avoiding memory corruption which can lead to issues like dangling references and memory

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leaks.

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It does this by restricting programmers from directly manipulating memory a process called Garbage collection

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is used for this which reclaim space occupied by dead or abandoned objects.

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Not that memory leaks are still possible in Java.

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However I suggested an effective Daleiden memory leaks can be avoided by ensuring that there are no

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obsolete object or Francis now when it comes to garbage collection there are two main challenges.

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One is to do with identifying and reclaiming data objects.

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What is garbage collectors employ mark and sweep kind of algorithms these algorithms would require pausing

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the application completely.

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And that leads to the second challenge which is how do we minimize such application pastimes to address

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this garbage can APIs use generational collection approach which mainly focuses on newly created objects

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and does not bother much about long living objects.

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Certain garbage collectors use features like multi-threading to further reduce the pastimes.

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Finally we look at few important bytecode instructions A-story instruction box data from the operand

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stack and start it at a specified index in the local variables are it a lot instruction does the exact

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opposite in what expression is used for invoking instance initialization methods private methods and

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methods of a superclass.

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We are the supercooled instance initialization methods are nothing but the constructors invoke virtual

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is used for invoking instance methods.

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No not that would invoke special and invoke virtual fusspot pop the top element on the operand stack

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of the current method unstarted at zero.

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And next in the local variables array of the Invoke method.

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OK so just keep that in mind.

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Another instruction is in static.

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It was discussed well covering method binding and it is used for invoking static methods.

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So that's about it.

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I think that's a pretty solid tradeoff JVM.

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It is more like a medium sized course on just JVM.

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So congratulations for completing the chapter.

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And thanks for listening and I will see you soon.

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Until then happy coding