Java Development Kit (JDK)

Definition: A software development kit used to create Java applications.
Components:

• Compiler (javac): Converts Java code (.java) into bytecode (.class).
• JRE: Runs Java programs.
• Development Tools: Debuggers, documentation generators, and class file disassemblers.
  Usage: Required for writing, compiling, debugging, and executing Java programs.

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Java Runtime Environment (JRE)

Definition: Provides the runtime environment for executing Java applications.
Components:

• JVM: Executes Java bytecode.
• Class Libraries: Essential libraries for running Java applications.
• GUI & Applet Components: Supports graphical user interfaces.
  Usage: Used by end-users to run Java applications without development tools.

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Java Virtual Machine (JVM)

Definition: A virtual engine that executes Java bytecode and provides platform independence.
Components:

• Class Loader: Loads and manages class files.
• Bytecode Verifier: Ensures bytecode security and correctness.
• JIT (Just-In-Time) Compiler: Enhances performance by compiling bytecode into native machine code at runtime.
  Usage: The backbone of Java’s “Write Once, Run Anywhere” capability.