Java Tutorial: Learn Java Programming From Scratch For Beginners

Java is one of the most popular and widely used programming languages out there. Thanks to its versatility and compatibility, Java finds applications in software development, mobile and desktop applications, large systems development, scientific supercomputers, game consoles, and several other instances. Of all the versions, Java 8 is extensively used for personal use and development. It contains new features, bug fixes, and enhancements for increased efficiency in developing and running Java programs. 

In this Java 8 tutorial for beginners, we will discuss some fundamental concepts like architecture, components of the Java programming language, features, different types of Java platforms, and more.

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What is Java?

Java is an object-oriented, multi-platform, secure, and high-level programming language. The project was initiated in 1991 by James Gosling, Patrick Naughton, and Mike Sheridan at Sun Microsystems. Initially, the project was called ‘Oak,’ named after an oak tree located outside Gosling’s office. It was then renamed ‘Green’ and finally ‘Java,’ after the Java coffee from Indonesia. The first public version of Java was released in 1995. Oracle owns Sun’s hardware and software product lines, including Java, after acquiring Sun Microsystems Inc. in 2010.

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Components of Java

Next, in this Java learning tutorial, we’ll look at some of the key components of the Java platform. These components translate the source code (human-readable language) into machine language or executable code. 

1. Java Development Kit (JDK)

The Java Development Kit or JDK is a complete software development environment for making Java applications and applets. It includes Java Runtime Environment (JRE), compilers, and various tools such as Java debugger, JavaDoc, etc. JDK helps users code, compile, and run Java programs, and it can be used on macOS, Windows, Linux, and Solaris. 

2. Java Runtime Environment (JRE)

Java Runtime Environment is a part of JDK and contains JVM, class libraries, applets support, and browser plugins. JRE must be installed in the system if a user wants to run Java programs.

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3. Java Virtual Machine (JVM)

The Java Virtual Machine or JVM executes the bytecode generated by the compiler and translates it into machine language. The program compilation is done by the javac compiler included in the Java Development Kit (JDK). The compiler takes the java program as input and returns Java bytecode as the output. Although each operating system has a different JVM, their output after executing the bytecode is the same across all operating systems. Thus, we say that Java is a platform-independent programming language.

Features of Java

A Java tutorial for beginners is incomplete without listing the main features of Java. These include:

• Java is a platform-independent programming language.
• The platform-independent nature of Java makes it portable. Thus, Java code written on one machine can run on other machines.
• Java is an Object-Oriented Programming language.
• Java is distributed. In other words, you can distribute Java programs across more than one system connected via the internet. 
• Java is a multithreaded language, meaning that it allows the simultaneous execution of two or more parts of a program for maximum CPU utilization.
•  Features like exception handling, garbage collection, and memory allocation make Java an extraordinarily robust and reliable language for the early detection of errors.
• Most importantly, Java is one of the easiest programming languages to learn!

Different Types of Java Platforms

The Java programming language has four platforms, each consisting of an application programming interface (API) and a JVM. The virtual machine and API allow the applications written for a particular platform to run on any compatible system. Following are the four Java platforms:

1. Java Platform, Standard Edition (Java SE)

The API of Java SE is packed with the core functionalities of the Java programming language. Apart from the core API, Java SE comprises a virtual machine, deployment technologies, development tools, and other toolkits and class libraries extensively used in Java applications.

2. Java Platform, Enterprise Edition (Java EE)

Built on top of the Java SE platform, Java EE contains the API and runtime environment for developing and running multi-tiered, scalable, reliable, secure, and large-scale network applications.

3. Java Platform, Micro Edition (ME)

The Java ME offers an API and a small footprint virtual machine used to run Java applications on small devices such as mobile phones. It is a subset of the Java SE API and contains special class libraries to develop small device applications. 

4. Java FX

Written in the Java FX ScriptTM, Java FX offers a lightweight user-interface API for creating rich internet applications. Applications written for Java FX are often clients of Java EE platform services and can include and link to Java classes.

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Types of Java Applications

You can use Java to create primarily four types of applications. These are as follows:

1. Web Applications

Web applications are the ones that run on the server-side and create a dynamic page. JSF, Hibernate, Spring, Struts, JSP, and Servlet are a few technologies currently used to develop web applications in Java.

2. Standalone Applications

Also known as window-based or desktop applications, standalone applications are traditional software that must be installed on every machine, such as anti-virus and media players. In Java, Swing and AWT are used for creating standalone applications.

3. Mobile Applications

These are applications created for mobile devices. Java ME provides a secure and flexible environment for developing applications targeted at mobile devices.

4. Enterprise Applications

An enterprise application is distributed in nature, such as a banking application. It comes with benefits like load-balancing and high-level security. In Java, enterprise applications are created using the EJB APIs. Learn more about Java applications.

Java Program Example

We will wrap up this Java tutorial for beginners with the classic “Hello World” program. But before executing any Java program, make sure the following requirements are fulfilled:

1. Download and install the JDK

2. Set the path of the jdk/bin directory

The “Hello World” Java program is as follows:

class Demo{  

    public static void main(String args[]){  

     System.out.println(“Hello World!”);  

    }  

}  

Output: Hello World!

Upon compilation of the Java program using the javac tool, the compiler translates the source code into the byte code. 

Parameters used in the Java example program

The above program has several parameters such as class, static, public, void, etc. Let’s see what each means:

• The term class is a keyword for declaring a class in Java.
• The term public is an access modifier and indicates visibility. Public means it is visible to all.
• The keyword static is a way of declaring a method. A method that has been declared status does not need an object to be invoked. The JVM executes the main() method and eliminates the need for creating an object to invoke main().
• The term void represents the return type of the method and means that the method doesn’t return any value.
• The term main marks the starting point of the program.
• String args[] is the array for the run time argument.
• System.out.println() is the print statement. Here, ‘System’ is a Java class, ‘out’ is an object of the PrintStream class, and ‘println’ is a method of the PrintStream class.

In advanced Java learning tutorials, you will learn Java concepts like class, method, object, etc.

This Java tutorial for beginners has been compiled keeping in mind those who are new to the Java programming language and need to understand its basic concepts. It offers a fundamental idea of what Java is, its components, features, the different Java platforms, and the various applications that can be built using Java. Last but not least, it offers a sneak peek into a beginner-level Java program to give readers a flavor of the programming language. The example program is accompanied by brief explanations of the various program parameters whose details will be clear in the advanced stages of Java learning.

Tips for Programming in Java for Beginners

Java is an extremely popular programming language among beginners. It enables programmers to write code and run it everywhere. If you need a Java tutorial for beginners, you must keep the following in mind:

• Be Careful with Strings

Two strings in Java might be concatenated with the help of the + operator in a loop. It results in the creation of a new String Object. It leads to memory wastage and might increase performance time. Instead, you should also be settling for the StringBuffer. 

• Perform Unit and Integration Testing

You can test the accuracy of source code behavior with the help of unit testing. These tests help you detect software bugs that might have occurred due to recent modifications in the source code. 

You can opt for high code coverage to go ahead with feature implementation without too many manual tests. You can use technologies like TestNG, JUnit, Mockito, PowerMock, and AspectJ to accommodate unit and integration tests. 

• Choose Interface Over Abstract Class

Java does not include too many inheritances. But the UI makes it easy to write a simple Java program for beginners with the help of multiple inheritances without using any extended keywords. If things are running beyond your plan, an interface will be necessary. But an abstract class lacks the liberty of multiple modes despite the abstract methods. 

• Prioritize Primitive Classes

Primitive classes are usually faster than wrapper classes. The wrapper classes include information about the whole class. However, the primitive class only contains values. 

The wrapper classes often have to look after object values. Therefore, you might not get the intended result by comparing wrapper classes with primitive classes. 

• Understand the Concept of Array and ArrayList

One of the most valuable tips for programming in Java for beginners is to comprehend the difference between ArrayList and Array. Developers often find it challenging to decide whether to employ an ArrayList type or an Array-type data structure. Both of them come with individual characteristics that become beneficial in multiple situations. 

Arrays come with a fixed size. But an ArrayList has different size variations. You can change the elements inside an ArrayList quite easily. But modifying elements inside an Array will be comparatively difficult. 

• Make Use of Build Tools

While developing Java applications, you will be able to speed up the process with the help of build tools. Every Java developer needs to be familiar with tools like Maven, Gradle, and Ant. These tools can help you automatically perform manual tasks necessary for deployment. For instance, these tools will be able to help you with tasks like clearing caches, making file copies, and injecting properties. 

• Encode Using JSOM

JSON is the syntax necessary for exchanging and storing data. It is an easier alternative to XML. You can encode a conventional data structure using JSON and share it on a website. It is becoming more popular due to its light properties and weight. But remember to install the JSON analyzer before writing your code. 

Way Forward

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