Introduction

 

§  Java Development Kit (JDK)

Oracle Corporation's Java Development Kit (JDK) is a Java Technology distribution. It implements the Java Language Specification (JLS) and the Java Virtual Machine Specification (JVMS), as well as the Java Application Programming Interface Standard Edition (SE) (API). It is a fork of the community-driven OpenJDK, which Oracle manages. It offers software for interacting with Java applications. The virtual machine, a compiler, performance monitoring tools, a debugger, and other utilities that Oracle considers useful for a Java programmer are examples of included software.

§  Java Runtime Environment (JRE)

The Java Runtime Environment, or JRE, is a software layer that runs on top of a computer's operating system software and provides the class libraries and other resources required to run a Java programme.

The JRE is one of three interconnected components used to develop and run Java programmes.

§  Java Virtual Machine (JVM)

A Java virtual machine (JVM) is a virtual machine that allows a computer to run Java programmes as well as other languages that have been compiled to Java bytecode. A specification that formally describes what is required in a JVM implementation details the JVM. A specification ensures Java programme interoperability across different implementations, so that programme authors using the Java Development Kit (JDK) do not have to worry about idiosyncrasies of the underlying hardware platform.

 

Java Virtual Machine (JVM)

The Java Virtual Machine (JVM) serves as a run-time engine for Java applications. The JVM is responsible for calling the main method in java code. JVM is a component of JRE (Java Runtime Environment).

WORA refers to Java applications (Write Once Run Anywhere). This means that a programmer can write Java code on one system and expect it to work on any other Java-enabled system without modification. All of this is made possible by the JVM.

When we compile a.java file, the Java compiler generates .class files (which contain byte-code) with the same class names as the.java file. When we run this .class file, it goes through several steps. These steps describe the entire JVM.