What is JVM

The Java Virtual Machine (JVM) is a software platform that executes Java code and provides a runtime environment for Java applications. It operates on the principle of Write Once, Run Anywhere (WORA).

The JVM is composed of the following components:

  1. Class Loader: Responsible for loading Java classes into the JVM.

  2. Execution Engine: The main component of the JVM, responsible for executing Java bytecode and providing memory management and garbage collection services.

  3. Java Heap: The memory space where objects and instances of classes are stored and managed.

  4. Java Stack: A per-thread stack data structure that stores frames, which contain method calls and their parameters.

  5. Program Counter Register: A register that keeps track of the current instruction being executed by the JVM.

  6. Native Method Stack: A stack for executing native methods written in languages other than Java.

  7. Method Area: A shared memory space where class-level information such as constant pool and class variables are stored.

  8. Register Set: A set of machine-level registers used to hold intermediate values and pointers during the execution of a method.

The JVM also provides several services such as memory management, thread synchronization, security, and others to support the execution of Java applications.