Head First to Java Core Programming

Here you can learn how Java program works. Let us see basic building blocks of Java programming language.

Introduction to Java

What is Java? Java is an object oriented programming language originally developed by Sun Microsystems. Java uses in millions of devices such as STB, Handheld Devices etc. Java referred as a pure object oriented programming language. Java contains a broad set of predefined classes and methods that handle most of the fundamental requirements of programs. Java uses virtual machine for executing programs. One of the key elements of java language is platform independence, Java program written on one platform may be deployed on any other platform. Java also contains a number of utilities for smart development. These utilities handle operations, such as debugging, deployment, and documentation. Java is a cross platform language, executes multiple platforms like Linux, Windows and Mac OS X.

Installing Java on your Computer

You can download the latest version of Java Development Kit (JDK) from official site of oracle Download JDK

Why do companies use Java ?

Object Oriented:

An object is an entity that has data attributes, plus a set of functions that is used to manipulate the object.

Interpreted and platform Independent:

Java programs are interpreted to the native machine's instruction set at the time. Because Java executes under the control of JVM. Java program can run any operating system that provides a JVM.

Dynamic and Distributed:

Java classes can be downloaded dynamically over the network when required. Java provides extensive support for client-server and distributed programming.

Multi-threaded:

Java programs can contain multiple threads to carry out many tasks in parallel. Multi threading capability is built into Java and is under control of the platform dependent JVM.

Robust and Secure:

Java has built in capabilities to prevent memory corruption. Java automatically manages the process of memory allocation and array bounds checking. Java prohibits pointer arithmetic. And restrict objects to named space in memory.

Java Virtual Machine 

1.    Java code is stored as a .java file

2.    The .java program is compiled, and generates .class files.

3.    Bytecodes are interpreted at run time.

Object Oriented Paradigm

  The basic idea of OOP is to combine both data and its functions that operate on the data into a single unit is called Object. Object oriented programming expresses programs in this ways that model how people receive the world.

Idea of Object Oriented Approach

What is Object?

An object is related to a real world entity. In Java everything associated with Object. Objects are communicated with each other for solving a problem.

What is Class?

A class serves as a plan or template. The programmer has to specify the entire set of data and function for various operations on the data for an object as a user defined type in the form of a class.

The programmer defines the object of similar type.

Encapsulation

The wrapping up of data and function into a single unit is known as Encapsulation. Data are hidden from outside access. This enables security. Encapsulation is one of the striking features of Object Oriented Approach. Data is not directly accessible to the outside world. Which are wrapped in the class.

Abstraction

Abstraction refers the act of representing essential features without explaining the background details to distinguish objects or function from other object or function.

Inheritance

Inheritance is a process by which objects of one class acquire the properties of objects of another class in the hierarchy. Main advantage of this approach is code re-usability.

Polymorphism

Polymorphism means the ability to take more than one form of the same property.