Difference Between JDK, JRE, and JVM in Java – Complete Explanation

By Bhau Automation • Understand JDK, JRE, JVM Architecture & Execution Flow

🎯 What You Will Learn in This Video

What is JVM (Java Virtual Machine)?
What is JRE (Java Runtime Environment)?
What is JDK (Java Development Kit)?
How JVM, JRE, and JDK are connected
JVM Architecture and Execution Engine
Difference between JDK, JRE, and JVM with examples

💡 Pro Tip: Understanding the difference between JDK, JRE, and JVM helps you troubleshoot Java setup issues and write better programs.

📌 What is JVM (Java Virtual Machine)?

JVM stands for Java Virtual Machine. It is the engine that executes Java bytecode. The JVM converts bytecode (.class files) into machine code that your system can understand.

Key Responsibilities of JVM:

Loads Java bytecode into memory
Verifies and executes bytecode
Manages memory (Garbage Collection)
Ensures platform independence for Java

⚙️ JVM Architecture Overview

The JVM consists of multiple components such as:

Class Loader: Loads class files into JVM.
Method Area: Stores class-level data.
Heap: Stores objects and runtime data.
Stack: Holds local variables and function calls.
Execution Engine: Executes bytecode instructions.
JIT Compiler: Improves performance by converting bytecode into native code.

💻 What is JRE (Java Runtime Environment)?

JRE stands for Java Runtime Environment. It provides the libraries, JVM, and other components required to run Java applications. JRE = JVM + Libraries + Java Class Files.

In short, JRE is required to run Java programs, but not to develop them.

🧰 What is JDK (Java Development Kit)?

JDK stands for Java Development Kit. It is the complete software development kit used to develop Java applications and applets.

JDK includes:

Compiler (javac)
JRE (Java Runtime Environment)
Debugger, Javadoc, and development tools

🧠 Remember: JDK = JRE + Development Tools, and JRE = JVM + Libraries.