What is JDK,JRE & JVM | What is the Architecture of Java?

 

What is JDK ?

JDK stands for Java Development Kit. It is a software development environment used for developing Java applications and applets. 

It includes the Java Runtime Environment (JRE), as well as command-line development tools such as compilers and debuggers.

What is JRE ?

JRE stands for Java Runtime Environment. It is a set of software tools for running Java applications. 

The JRE includes the Java Virtual Machine (JVM), as well as the Java class libraries, which provide the functionality required by Java applications.

What is JVM ?

JVM stands for Java Virtual Machine. It is a program that runs Java bytecode, which is the intermediate language that Java source code is compiled into. 

The JVM interprets the bytecode and executes the corresponding actions on the host computer's operating system.

In summary, JDK is a software development kit and it includes JRE and other development tools. JRE is a set of tools that is required to run Java applications and it includes JVM. JVM is the heart of Java, it is the virtual machine that runs the bytecode generated by the compiler and provides the platform independence to the Java.

The architecture of Java can be broadly divided into two parts:

The Java Virtual Machine (JVM): 

• This is the virtual machine that runs the Java bytecode, which is the intermediate language that Java source code is compiled into. 

• The JVM interprets the bytecode and executes the corresponding actions on the host computer's operating system. 

• It provides the platform independence of Java, as the same bytecode can run on any platform that has a JVM.

The Java Application Programming Interface (API): 

• This is a set of classes and interfaces that provide the functionality required by Java applications. 

• The API is divided into several packages, such as java.lang, java.io, and java.util, which contain classes for basic data types, input/output, and utility functions, respectively. 

• The API also includes the Abstract Window Toolkit (AWT) and Swing, which are used for creating graphical user interfaces (GUIs).

Together, the JVM and the API form the foundation of the Java platform. When a Java program is executed, the JVM loads the bytecode and executes it, using the classes and interfaces provided by the API to perform various tasks.

Additionally, Java SE (Standard Edition) and Java EE (Enterprise Edition) are two more components of Java architecture, Java SE provides a basic set of libraries and tools, while Java EE provides a more complete set of libraries, tools and technologies for developing enterprise level applications.