Java Overview

JRE and installation

What is JRE (Java Runtime Environment)?

The Java Runtime Environment (JRE) is a software package that is needed to run Java programs. It includes the Java Virtual Machine (JVM), which is responsible for executing Java bytecode, as well as a number of other components that are necessary for Java programs to run. The JRE is platform-independent, which means that it can be used to run Java programs on a variety of different operating systems. This is one of the key strengths of the Java platform, as it makes Java code portable and scalable. The JRE is divided into two main components: Java Virtual Machine (JVM) is responsible for executing Java bytecode. The JVM is platform-specific, which means that there is a different JVM for each operating system that supports Java. Java Class Library (JCL) is a library of classes that Java programs can use. The JCL includes classes for things like I/O, networking, and graphics. The JRE also includes a number of other components, such as: A garbage collector, which automatically deallocates memory that is no longer being used by Java programs. A security manager, which prevents Java programs from accessing system resources that they are not authorized to access. A debugger, which can be used to step through Java programs line by line. The JRE is an essential part of the Java platform, and it is required to run Java programs. If you are interested in developing Java programs, you will need to install the JRE on your computer. Here are some additional details about the JRE: The JRE is typically bundled with the Java Development Kit (JDK), which is a software development environment that is used to develop Java programs. The JRE can be downloaded from the Oracle Java SE Downloads page: https://jdk.java.net/18/ The JRE is also available as a pre-installed component on many operating systems, such as macOS and Windows.

Java Runtime Environment (JRE) installation

How to Install Java Runtime Environment (JRE) on Windows OS

The steps on how to install the Java Runtime Environment (JRE) on Windows: Step 1 : Go to the Oracle Java SE Downloads page: https://jdk.java.net/18/ Step 2 : Click the Java SE Development Kit 18 (JDK) link. Step 3 : On the next page, click the Windows x64 link to download the JRE for 64-bit Windows. Step 4 : Once the download is complete, run the installer. Step 5 : Follow the on-screen instructions to complete the installation. Step 6 : You can verify that the JRE is installed correctly by opening a command prompt and typing the following command:

java -version

This command should print the version of the JRE that is installed on your system.

How to Install Java Runtime Environment (JRE) on LinuxOS

The steps on how to install the Java Runtime Environment (JRE) on Linux: Step 1 : Open a terminal window. Step 2 : Update your package manager:

sudo apt update

Step 3 : Install the JRE:

sudo apt install openjdk-18-jre

Step 4 : Verify that the JRE is installed correctly:

java -version

This command should print the version of the JRE that is installed on your system.

How to Install Java Runtime Environment (JRE) on macOS

The steps on how to install the Java Runtime Environment (JRE) on macOS: Step 1 : Open a Terminal window. Step 2 : Update your package manager:

brew update

Step 3 : Install the JRE:

brew install openjdk

Step 4 : Verify that the JRE is installed correctly:

java -version

This command should print the version of the JRE that is installed on your system.