Java Tutorial

What is Java?

Java is a high level, general-purpose, objected-oriented programming language. However, it is not considered pure object-oriented, because:

• It provides support for primitive data types like int, char, etc which are non-object,
• In a pure OOP language, we should access everything by message passing through objects but in Java we have static variables and methods that can be accessed directly without the objects.

It was developed by James Gosling at Sun Microsystems in 1995. Java applications are run by a run time engine called JVM, Java Virtual Machine, they are also called WORA, which stands for Write Once Read Anywhere. WORA, basically means, Java code compiled on one system can run on all other Java-supported systems without the need for any recompilation. In Java, programs are compiled into byte code and the byte code is executed by the JVM making the byte code platform-independent. When compared to other programming languages, Java is faster than Python due to its support for concurrency and multithreading features, code written in Java is more maintainable than of C++. The learning curve for Java is low, leading to better developer access.

Java programming example

Let's quickly review an example of Java programming. This is a description in more detail of the Hello Java example.

public class HelloWorld {  
    public static void main(String args[]) {  
     System.out.println("Hello World! Welcome to Java Programming.");  
    }  
}  

Output:

Hello World! Welcome to Java Programming.

Applications of Java

Mobile Applications: Java language provides a cross-platform framework called J2ME to develop mobile applications. Android application development is based on top of Java. Netflix, Uber, etc are also Java-based.

Desktop Applications: Several desktop tools, Acrobat Reader for example are developed using Java. Tools like JavaFX, Java Foundation classes help in the creation of desktop applications.

Web Applications: Several Tech Giants like Amazon have their web applications built on Java. JSP(Java Servlet Programs) Struts, Spring, Hibernate, JSF are some of the technologies for creating web applications in Java.

Enterprise Applications Applications are created to satisfy the needs of an entire organization than an individual. Java is the most preferred language in this domain. As per Oracle, 97% of the total enterprise applications are built on Java.

Web Servers & Applications Servers: Java ecosystem provides a huge number of web servers and application servers. As for web servers Apache Tomcat, Rimfaxe Web Server(RWS), Project Jigsaw etc are all based on top of Java. For application servers, we have JBoss, WebSphere, WebLogic, etc.

What are the Types of Java Programs?

Mainly you can create the following programs using Java.

• Standalone Programs Standalone Programs also called desktop applications, are the software that require to be installed on each system before being run. These are freestanding programs that function on their own and do not require any services of OS to run. Example - Media Player,Text Editors,Antivirus etc
• Java Applets Java applets are small Java programs that can be executed on a client computer with a web browser after being downloaded from a website.
• Java Servlets Java Servlets run on web servers or application servers and are used to generate web applications. Servlets basically handle the requests sent to web servers by clients. For execution, servlets process these requests and produce a response, to be sent back to the webserver.
• Enterprise Programs As discussed earlier, these are distributed applications, a little complex in nature. EJB(Enterprise Java Bean) a Java tool, helps in building these programs.
• JAR Files JAR stands for Java Archive. JAR files are used to package multiple Java files together into a single file, analogous to zip files.

Platforms or Editions of Java

1. Java Platform, Standard Edition (Java SE) : The foundational programming elements of Java are provided via the APIs (Application Programming Interfaces) that make up the Java Platform Standard Edition (Java SE).

2. Java Platform, Enterprise Edition (Java EE) : A set of standards and specifications that describe frequently used functionality by commercial applications were added to the Java SE to expand it, creating the Java Enterprise Edition (Java EE).

3. Java Platform, Micro Edition (Java ME) : Java Micro Edition was created to support applications for embedded and mobile devices. Although this edition is not as well-known as others like Java SE and Java EE, the Internet of Things (IoT) devices have recently given this technology new hope.

4. JavaFX : Rich internet apps, GUI applications, and desktop applications can all be created using the JavaFX platform, which makes use of a straightforward user-interface API. As the new standard GUI library, it was developed in Java to replace Swing.

For more details, refer Types of Java.

What will you Learn in This Java Tutorial?

In this Java tutorial you should learn about :

• Introduction to java
• Installation and set-up procedures for Java
• Basic Java syntax and constructs.
• Java Classes and Interfaces
• Java Functions
• Java Data Structures
• Java OOP concepts
• Java File Handling

Why Should You Learn Java Programming?

Java, other than being reliable and secure, it is :

• Easy to learn: Java syntax is clear and concise, thus easy to learn.
• Platform-independent: Java supports WORA and provides cross-platform benefits, so code written in Java can run on any Java-supported platform.
• Multithreaded language: Threads are lightweight sub-processes. Java can define multiple threads and thus execute multiple tasks at the same time.
• Robust: Java provides robust tools such as better inbuilt exception and error handling, helping build reliable and error-free programs. Java is also secure since these programs run inside a virtual machine which is known as a sandbox. Java also doesn't support explicit pointers leading to more security.
• Object Oriented: Java is a class-based, object-oriented programming language. Thus, you can leverage and benefit from the OOP features.
• Needs no pre-processor don't need to include any header files to create Java applications.
• Great demand in the industry: Billions of devices run on Java and being in great demand offers highly paid jobs.

How Can You Learn Java?

So the question arises, how to start learning Java?

• Grip on Fundamentals: Try to learn the basic concepts first, before jumping to the advanced ones.
• Regular Practice: Once done with the fundamentals, code as much as you can. This shall help you discover several tricks and ideas to build better programs.
• Stay Updated on New Features: Many features get updated with the release of newer Java versions, so read about Java regularly and stay updated.
• Great things come out of patience: It may seem overwhelming in the beginning, but patience is the key. Try to understand the core concepts first, only a strong foundation shall help you build great things.

Career Opportunity of Learning Java Programming

It is clearly visible that career opportunities in Java will not fade anytime soon. By learning, you can be a:

• Web Developer
• Game Developer
• Android Developer
• Scientific Applications Developer
• Enterprise Application Developer
• Java Architect
• Software Developer

Audience

In order to help beginners grasp Java programming from its fundamentals to its more complex ideas, this tutorial has been created.

Your degree of Java proficiency will be moderate after finishing this tutorial, from which point you can advance.

Pre-requisite

Despite the fact that it is a beginner's course, we presume that the readers have some familiarity with programming environments and a working knowledge of fundamental ideas like variables, commands, syntax, etc.