WIL : Java Virtual Machine (JVM) / Java Runtime Environment (JRE)

In the process of learning Java, I noticed that the word Java Virtual Machine(JVM) comes out quite often.

What is JVM?

A Java Virtual Machine is a virtual machine that enables a computer to run Java Programs as well as programs written in other languages that are also compiled to Java bytecode. It is known as the interpreter or the core of Java programming language since it executes Java programming.

what does JVM do?

It is responsible for converting bytecode to machine specific code and is necessary in both JDK and JRE. It is also platform dependent and performs many functions, including memory management and security. Also, JVM can run programs written in other languages that have been translated to Java bytecode.

JVM Components

• Class Loader Subsystem: responsible for loading, linking and initializing a Java class file, otherwise known as dynamic class loading.

• Runtime Data Areas: containing an interpreter, compiler and garbage collection area.

What is Java Runtime Environment (JRE) ?

Set of software tools responsible for execution of the Java program or application on your system.

JRE uses heap space for dynamic memory allocation for Java objects.

JRE Components

• Deployment solutions : Included as part of the JRE installation are deployment technologies like Java Web Start and Java Plugin that simplify the activation of applications and provide advanced support for future Java updates.

• Development toolkits: help developers imporve their user interface.

• Integration libraries: to assist developers in creating seamless data connections between their applications and services.

• Language and utility libraries: fundamental for the design of Java applications, package versioning, management and monitoring.