Why Java?

Today Java is most widely used programming language by developers worldwide. The main characteristics of Java language that make it so popular are:

Object Oriented – Yes, you can create objects – pieces of autonomous code – that can interact with other objects to solve a problem. These objects provide a modular design, information-hiding capability and code-reuse facility.

Distributed – The Java programming language is considered a distributed language because it provides support for distributed network technologies such as Remote Method Invocation, or RMI, Common Object Request Broker Architecture, or CORBA, and Universal Resource Locator, or URL.

Simple –  It does not allow programmers to directly manipulate pointers to memory locations – a complex feature of the C or C++ and Java Boolean can have only true or false value. Yes…the designers have removed some of the complex or obscure programming constructs that are found in other popular programming languages and it makes Java a simple language.

Multi-threaded – It allows several tasks to run concurrently and as a result Java technology programs are very efficient in its use of system resources.

Secure – Java technology programs are secure because the Java programming language and the Java environment in which Java programs run, use security measures to protect programs from attacks.

Platform independent – Unlike languages such as C and C++, the Java programming language is platform independent. A Java technology program can run on several different CPUs and operating system combinations, usually with few or no modifications.

Some frequently asked questions about Java

What is Java applet?

Java Applets is a java program that is launched from HTML and run in a web browser. Applets are used to provide interactive features to web applications that cannot be provided by HTML alone.

What is the difference between Java Applets & Java Applications?

The main difference between applets and applications is that applets are launched inside a web browser, while applications are launched within an operating system.

What is Java technology bytecode?

Java technology programs are compiled using a Java technology compiler. The resulting format of a compiled Java technology program is platform-independent Java technology bytecode.

What is Java Virtual Machine (JVM)?

A virtual machine is a platform-specific program that understands platform-independent bytecode and can execute it on a particular platform. For Java technology programs to be platform independent, a virtual machine or JVM is required on every platform where a program will run.

How Java Virtual Machine (JVM) got it’s name?

A virtual machine got its name because it is a piece of software that runs code, a task usually accomplished by the CPU or hardware machine.

What is Java Run Time Environment (JRE)?

A Java technology program needs more than just a Java Virtual Machine to execute. A Java technology program also needs a set of standard Java class libraries for the platform. Java class libraries are libraries of pre-written code.  These Java class libraries can be combined with the code that you write to create robust applications. Combined, the JVM software and Java class libraries are referred to as the Java run time environment, or JRE.

What are different Java platforms?

Java SE: The Java Platform Standard Edition, or Java SE, is used to develop applets that run within web browsers and applications that run on servers and desktop computers such as a word-processing program for a personal computer.

Java EE: The Java Platform Enterprise Edition, or Java EE, is used to create large enterprise, server-side, and client-side distributed applications such as eCommerce application for a retail company’s web site. Java EE is built on top of the Java SE Platform, extending it with additional APIs supporting the needs of large-scale, high-performance enterprise software.

Java ME: Java Platform Micro Edition, or Java ME, is used to create applications for resource-constrained consumer devices. For example to create a game that runs on a cellular phone. Blu-ray Disc Java applications and Java TV use the same SDK as Java ME.

Java Card: Java Card enables devices with a small memory -footprint to run applets. 

What is Java Development Kit?

The Java Development Kit (JDK) is a software development environment used for developing Java applications and applets.  Each of Java edition includes a Java Development Kit, or JDK. The JDK allows programmers to create, compile, and execute Java technology programs on a particular platform. For example, you can use the Java EE JDK to create an eCommerce  application. Java ME JDK to create a game that runs on a cellular phone. A JDK is also known as a Software Development Kit, or SDK.

What is an Integrated Development Environment (IDE)?

An Integrated Development Environment, or IDE, is a tool that can assist you with developing your Java application. There are several IDEs that you can use, for example, NetBeans, JDeveloper, or Eclipse.

Setting Up Java Development Environment

To set up Java development environment on your machine, you can download the JDK, or Java Development Kit from the Oracle Java web site for free.

When you download and install the Java Development Kit, these items are installed:

• Java runtime environment, or JRE
• a Java Virtual Machine, or JVM, for the platform you use
• Java class libraries for the relevant platform
• a Java technology compiler
• additional utilities, such as utilities for creating Java archive, or JAR, files, and for debugging Java technology programs, and
• examples of Java technology programs