Скачать или смотреть JVM, JRE in Java | JVM vs JRE in java programming |Java virtual machine | Java Runtime Environment

Definition:

JVM stands for Java Virtual Machine.
It is a virtualized runtime environment that executes Java bytecode.
It abstracts the underlying hardware and provides a consistent environment for Java programs to run on different platforms without modification.
Functionality:

JVM is responsible for executing Java applications by interpreting or compiling Java bytecode into machine code.
It provides memory management, garbage collection, and runtime environment for Java applications.
Platform Independence:

One of the key features of JVM is platform independence. Java bytecode is platform-neutral, and JVM interprets or compiles this bytecode into platform-specific machine code during runtime.
Components:

JVM consists of three main components: Class Loader, Execution Engine, and Java Native Interface (JNI).
Class Loader: Loads class files into memory.
Execution Engine: Executes Java bytecode.
JNI: Provides a bridge between Java and native application code.
Java Runtime Environment (JRE):
Definition:

JRE stands for Java Runtime Environment.
It is a software package that includes JVM, Java Standard Edition (Java SE) libraries, and additional components required for running Java applications.
Components:

JRE includes the JVM and a set of libraries and frameworks, such as the Java API (Application Programming Interface) classes, that are necessary for running Java applications.
Functionality:

JRE provides the runtime environment for Java applications, allowing them to be executed on a computer or device.
It includes tools like the Java Debugger and other utilities for monitoring and troubleshooting Java applications.
Deployment:

JRE is typically used for deploying Java applications on end-user machines. End users need to have JRE installed to run Java applications without needing the full development environment.
Relationship between JVM and JRE:
JVM is a subset of JRE:

JRE includes the JVM along with libraries and additional components.
JRE is a complete package for running Java applications, while JVM is specifically responsible for executing Java bytecode.
JVM is platform-dependent, while JRE is platform-independent:

JVM is specific to the underlying hardware and operating system.
JRE, with its platform-independent Java libraries, allows Java applications to run on any system with the appropriate JRE installation.
In summary, JVM is the core component responsible for executing Java bytecode, while JRE provides the runtime environment and includes the JVM along with libraries and tools needed for running Java applications. The full Java Development Kit (JDK) includes both JRE and additional development tools for compiling and building Java applications.