Java JDK, JVM and JRE

698

Java is a popular programming language used for developing a variety of applications, including desktop, mobile, web, and enterprise-level software. To work with Java, you need to understand some basic concepts, including the Java Development Kit (JDK), Java Virtual Machine (JVM), and Java Runtime Environment (JRE).

In this tutorial, we’ll cover the basics of JDK, JVM, and JRE in Java.

Java Development Kit (JDK)

The Java Development Kit (JDK) is a set of software tools used for developing and running Java applications. It includes the Java compiler, which converts Java source code into bytecode, and other tools needed for developing Java applications.

The JDK includes the following components:

1. Java Compiler: It is the tool that compiles Java source code into bytecode, which is then interpreted by the JVM.
2. Java Virtual Machine (JVM): It is the virtual machine that runs Java applications on a computer, regardless of the operating system.
3. Java Development Tools (JDT): It includes tools like the Eclipse IDE, which is used for developing Java applications.
4. Java Runtime Environment (JRE): It is the runtime environment for Java applications, which includes the JVM and other components necessary for running Java applications.

To download and install the JDK, follow these steps:

1. Go to the Oracle website and download the appropriate version of the JDK for your operating system.
2. Double-click the downloaded file to launch the installer.
3. Follow the prompts in the installer to install the JDK on your computer.

Once the JDK is installed on your computer, you can start developing Java applications using an IDE like Eclipse or IntelliJ IDEA.

Java Virtual Machine (JVM)

The Java Virtual Machine (JVM) is a virtual machine that runs Java bytecode. It is responsible for interpreting Java bytecode and executing Java applications on a computer, regardless of the underlying operating system.

The JVM provides a secure and platform-independent environment for running Java applications. It includes a Just-In-Time (JIT) compiler, which converts Java bytecode into machine code at runtime for faster execution.

The JVM is available on all platforms that support Java, including Windows, MacOS, and Linux.

Java Runtime Environment (JRE)

The Java Runtime Environment (JRE) is the runtime environment for Java applications. It includes the JVM and other components necessary for running Java applications.

The JRE is available for download separately from the JDK. If you only need to run Java applications on your computer, you can download and install the JRE instead of the full JDK.

To download and install the JRE, follow these steps:

1. Go to the Oracle website and download the appropriate version of the JRE for your operating system.
2. Double-click the downloaded file to launch the installer.
3. Follow the prompts in the installer to install the JRE on your computer.

Once the JRE is installed on your computer, you can run Java applications on your computer without needing to install the full JDK.

Conclusion

In this tutorial, we covered the basics of JDK, JVM, and JRE in Java. The JDK is a set of software tools used for developing and running Java applications, while the JVM is a virtual machine that runs Java bytecode, and the JRE is the runtime environment for Java applications.

Understanding these concepts is essential for working with Java and developing Java applications.