Java Runtime Environment (JRE)

The Java Runtime Environment (JRE) is a part of the [[Java Development Kit (JDK)]], a set of software tools used for developing [[Java]] applications. It provides the libraries, the [[Java Virtual Machine (JVM)]], and other components to run applications written in Java.

The JRE is specifically designed to provide an environment to execute Java applications. It cannot be used to develop applications, as it does not contain tools like compilers or debuggers.

Components of the JRE:

• Java Virtual Machine (JVM): The core of the JRE, the JVM is an engine that provides a platform-independent way of executing Java code. It converts Java bytecode into machine language and executes it.
• Java Class Libraries: A set of dynamically loadable libraries that Java applications can call at runtime.
• User Interface Toolkits: Such as the Abstract Window Toolkit (AWT) and Swing.
• Integration Libraries: That enable database access, remote object invocation, and other networking mechanisms.

One of the primary advantages of Java is its platform independence. Java applications compiled on one platform can run on any platform equipped with a compatible JRE. The JRE is a subset of the JDK. While the JDK is used for developing Java applications, the JRE is used for running them. The JDK includes the JRE along with compilers, debuggers, and other tools.

Some web browsers require the JRE for running Java applets (though Java applets are largely obsolete now). For a user to run Java applications, their machine must have the JRE installed. Developers typically bundle the JRE with their software or instruct users on how to download it.

Regular updates to the JRE are released to address security vulnerabilities and bugs, as well as to provide performance improvements.