Digital Kittu

• Java virtual machine:
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• JVM, i.e., Java Virtual Machine.
• JVM is the engine that drives the Java code.
• Mostly in other Programming Languages, compiler produce code for a particular system but Java compiler produce Bytecode for a Java Virtual Machine.
• When we compile a Java program, then bytecode is generated. Bytecode is the source code that can be used to run on any platform.
• Bytecode is an intermediary language between Java source and the host system.
• It is the medium which compiles Java code to bytecode which gets interpreted on a different machine and hence it makes it Platform/Operating system independent
• A specification where working of Java Virtual Machine is specified. But implementation provider is independent to choose the algorithm. Its implementation has been provided by Oracle and other companies.
• An implementation Its implementation is known as JRE (Java Runtime Environment).
• Runtime Instance Whenever you write java command on the command prompt to run the java class, an instance of JVM is created.
• The JVM performs following operation:
• Loads code
• Verifies code
• Executes code
• Provides runtime environment.                                  
• JVM generates a .class(Bytecode) file, and that file can be run in any OS, but JVM should have in OS because JVM is platform dependent.
• Java is called platform independent because of Java Virtual Machine. As different computers with the different operating system have their JVM, when we submit a .class file to any operating system, JVM interprets the bytecode into machine level language.
  • JVM is the main component of Java architecture, and it is the part of the JRE (Java Runtime Environment).
  • A program of JVM is written in C Programming Language, and JVM is Operating System dependent.
  • JVM is responsible for allocating the necessary memory needed by the Java program.
  • JVM is responsible for deallocating memory space.