JAVA – Difference between JDK, JRE, and JVM

JDK, JRE, and JVM are important components in the Java programming ecosystem. Here’s a breakdown of the differences between them:

1) JDK (Java Development Kit):
The JDK is a software development package that provides tools, libraries, and documentation necessary for developing Java applications. It includes the Java compiler (javac), which translates Java source code into bytecode, and other development tools like debuggers and profilers. The JDK also includes the JRE (Java Runtime Environment) since it is required for compiling and running Java programs. In addition, the JDK contains development-specific libraries and APIs that developers can utilize when building Java applications.

2) JRE (Java Runtime Environment):
The JRE is a runtime environment that provides the necessary components to run Java applications. It includes the Java Virtual Machine (JVM), class libraries, and other runtime libraries required for executing Java programs. The JRE does not contain the development tools present in the JDK. Therefore, if you only want to run Java applications and don’t need to develop them, you can install the JRE instead of the JDK.

3) JVM (Java Virtual Machine):
The JVM is a virtual machine that executes Java bytecode. It is the runtime component responsible for interpreting or Just-In-Time (JIT) compiling the bytecode into machine code that can be executed by the underlying operating system. The JVM is platform-specific, meaning there are different implementations of the JVM for different operating systems. It provides features like memory management, garbage collection, and security to ensure the safe execution of Java programs.

To summarize:

• JDK: It is the complete software development package that includes the tools, libraries, and documentation required for developing Java applications. It also includes the JRE.
• JRE: It is the runtime environment needed for running Java applications. It includes the JVM and necessary libraries but lacks the development tools present in the JDK.
• JVM: It is the virtual machine responsible for executing Java bytecode and providing various runtime services like memory management and security.

In general, if you’re planning to develop Java applications, you’ll need to install the JDK. If you only want to run Java applications, you can install the JRE. The JVM is an integral part of both the JDK and JRE and is responsible for executing the Java bytecode on the target platform.