What is the difference between JDK, JRE and JVM

The content of this article is to introduce what JDK, JRE and JVM are respectively, so that everyone can understand the differences between JDK, JRE and JVM. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

JVM

JVM (Java Virtual Machine) is an abstract machine. It's called a virtual machine because it doesn't actually exist. It is a specification that provides a runtime environment that can execute Java bytecode. It can also run programs written in other languages ​​and compiled to Java bytecode.

JVM is available for many hardware and software platforms. JVM, JRE and JDK are platform dependent as the configuration of each operating system is different from each other. However, Java is platform independent. JVM has three concepts: specification, implementation and instance.

JVM mainly performs the following tasks:

1. Loading code

2. Verification code

3. Execution code

4. Provide runtime environment

JRE

JRE is the acronym for Java Runtime Environment, also known as Java RTE; it is the JVM's Realization is something that actually exists.

JRE is a set of software tools for developing Java applications to provide a runtime environment; it contains a set of libraries and other files used by the JVM at runtime.

JDK

JDK is the acronym for Java Development Kit, which is a software development environment for developing Java applications and applets ; it actually exists. It contains JRE development tools.

JDK contains a private Java Virtual Machine (JVM) and some other resources such as interpreter/loader (java), compiler (javac), archiver (jar), documentation generator (Javadoc), etc. , to complete the development of Java applications.

Summary of the differences between JVM, JRE, and JDK:

JVM is a specification that provides a runtime that can execute Java bytecode time environment.

JRE = JVM library for running Java applications.

JDK = JRE Tools for developing Java applications.

The relationship diagram between the three:

The above is the entire content of this article, I hope it can help everyone learn Helps. For more related video tutorials, please visit: JavaTutorial!

The above is the detailed content of What is the difference between JDK, JRE and JVM. For more information, please follow other related articles on the PHP Chinese website!