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.

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

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

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

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

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

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

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

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