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What are JDKs, JREs, and JVMs in Java?

JVMs in Java

Most novice Java programmers immediately begin to learn the basic constructs of the language, syntax and rules without thinking about what , and . They simply miss this question without understanding the difference and what they are intended for, and . Therefore, in this article I will try to explain the difference between these concepts of the Java language.


In a nutshell about JDK, JRE and JVM

  • The JDK is needed for development (compiler, debugger, etc.).
  • The JRE is needed to run Java programs (contains the JVM).
  • The JDK and JRE contain the JVM that is needed to run Java programs.
  • The JVM is the heart of the Java programming language and provides platform independence.

What is the Java Development Kit (JDK)?

Java Development Kit is a core component of the Java environment and provides all the tools, executables, and binaries needed to compile, debug, and execute a Java program. The JDK is platform-dependent software, so there are separate installers for Windows, Mac, and Unix systems. You can say that it is an add-in because it contains with a Java compiler, debugger, and base classes. The current version of JDK 1.8 is also known as Java 8.


What is the Java Virtual Machine (JVM)?

JVM is the heart of the Java programming language. When we run a program, it is responsible for converting the bytecode into machine code. The JVM is also platform-specific and provides basic functions such as Java memory management, garbage collection, etc. We can also allocate a certain amount of memory to the JVM. The JVM is a virtual machine because it provides an interface that is independent of the operating system and hardware. This independence from hardware and operating system gives Java programs the ability to run on any device without having to make changes — Write once, run anywhere.


What is the Java Runtime Environment (JRE)?

JRE is an implementation that provides a platform for executing Java programs. consists of a Java virtual machine, binaries, and other classes. does not contain development tools (Java compiler, debugger, etc.). If you want to run any Java program, you must install .


Just-in-time Compiler (JIT) in Java

The Just-in-time Compiler (JIT) is part of the JVM. It optimizes bytecode by reducing the total time it takes to compile bytecode into machine code.