Java

Introduction

Java is an object-oriented programming (OOP) language.
The Java programming language is the language in which Java applications, applets, servlets, and components are written. When a Java program is compiled, it is converted to byte codes that are the portable machine language of a CPU architecture known as the Java Virtual Machine (also called the Java VM or JVM). The JVM can be implemented directly in hardware, but it is usually implemented in the form of a software program that interprets and executes byte codes.

The Java Virtual Machine

It is a virtual (or "pretend") machine inside your computer. Does everything a computer is expected to such as perform calculations, manipulate memory, produce output
… but it exists only in software!

This Java Virtual Machine takes Java Byte Code instructions one by one. Translates them into machine language for the given platform. Executes the machine language and produces desired results.

The Java Virtual Machine is different for every computer that is, there is one that generates PC
instructions, one that generates Mac instructions, and so on.
It has to be a different virtual machine for each platform as every machine has a different
machine language.

You quite likely have used a Java Virtual Machine before, but did not realize it.
Most web browsers come with the Java Virtual Machine.

Processing Java - Summary

- Source code is written in Java, a high-level language
- This Java source code is run through a Java compiler
- The Java compiler doesn’t produce machine language,
but instead produces generic Java Byte Code,
-Java Byte Code is then interpreted by the Java Virtual Machine to produce desired results.

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