#JVM Architecture in Java Hindi by Deepak

[smartprogramming]

Virtual Machine - Virtual Machine is a software simulation of a machine which can perform operations similar to physical machine. - Virtual Machine is not physically present. - A virtual machine, usually known as a guest is created within another computing environment referred as a "host." Multiple virtual machines can exist within a single host at one time. - For eg. Calculator software in operating system, which is not physically present, but performs all the functions similar to physical calculator. - Types of Virtual Machine : 1. Hardware Based or System Based Virtual Machine 2. Application Based or Process Based Virtual Machine - JVM (Java Virtual Machine) is Application Based Virtual Machine. ------------------------------------------------------------------------------------------ Java Virtual Machine (JVM) : - It is a Runtime Engine responsible to run java based applications. - It has two main tasks : 1. load .class file 2. execute .class file - Main components of JVM : 1. Class Loader 2. Memory Areas 3. Execution Engine ---------------------------------------------------------------------------- Class Loader : - It is responsible for the following three tasks :         1. Loading 2. Linking 3. Initialisation - Loading - Linking : In linking three activities are performed :  1. Verification  2. Preparation 3. Resolution - Initialisation ------------------------------------------------------------------------------------ Memory Areas : Total 5 types of memory areas : 1. Method Area           2. Heap Area 3. Stack Area 4. PC Register           5. Native Method Area ------------------------------------------------------ Execution Engine : It  is responsible to execute java class file. It contains mainly two components : 1. Interpreter 2. JIT Compiler

[smartprogramming]

Virtual Machine - Virtual Machine is a software simulation of a machine which can perform operations similar to physical machine. - Virtual Machine is not physically present. - A virtual machine, usually known as a guest is created within another computing environment referred as a "host." Multiple virtual machines can exist within a single host at one time. - For eg. Calculator software in operating system, which is not physically present, but performs all the functions similar to physical calculator. - Types of Virtual Machine : 1. Hardware Based or System Based Virtual Machine 2. Application Based or Process Based Virtual Machine - JVM (Java Virtual Machine) is Application Based Virtual Machine. ------------------------------------------------------------------------------------------ Java Virtual Machine (JVM) : - It is a Runtime Engine responsible to run java based applications. - It has two main tasks : 1. load .class file 2. execute .class file - Main components of JVM : 1. Class Loader 2. Memory Areas 3. Execution Engine ---------------------------------------------------------------------------- Class Loader : - It is responsible for the following three tasks :         1. Loading 2. Linking 3. Initialisation - Loading - Linking : In linking three activities are performed :  1. Verification  2. Preparation 3. Resolution - Initialisation ------------------------------------------------------------------------------------ Memory Areas : Total 5 types of memory areas : 1. Method Area           2. Heap Area 3. Stack Area 4. PC Register           5. Native Method Area ------------------------------------------------------ Execution Engine : It  is responsible to execute java class file. It contains mainly two components : 1. Interpreter 2. JIT Compiler