Java is one of the most preferred programming languages used by web developers. It is a high-level, object-oriented programming language used for developing web applications, mobile apps, and enterprise-level applications. Sun Microsystems introduced Java technology in 1995, and several versions have been released since.

Java is famous for being platform-independent, meaning it can run on any operating system without being rewritten. This article covers Java basics for beginners. So keep reading to learn simple Java programs for beginners.

Key Highlights

• The Java Virtual Machine is the interpreter or the core of Java programming language because it loads, executes, and verifies Java bytecode
• Java technology is versatile and used to build diverse applications, including web, enterprise, game, and mobile apps
• Every programing language has its syntax and human language, and Java syntax is identical to other programming languages
• As a beginner, you must learn basic Java concepts, like Object-Oriented Programming Concepts and exception handling
• You can start learning Java with basic programs like the Even or Odd Program and Fibonacci Series, and build more complex programs as you progress

Java Development Kit (JDK)

One of the Java basics for beginners is the Java Development Kit and Software Development Kit (SDK). You can use both to develop applications. SDK is primarily for mobile application development, while JDK is for Java application development.

The Java Development Kit includes the Java Runtime Environment (JRE) for running Java applications and tools. Examples of these apps and devices are Java debugger, Java compiler, and Java documentation generator. Before you start writing Java programming language, download and install the JDK on your computer.

Java Virtual Machine (JVM)

A Java Virtual Machine enables a computer to run Java programs and execute the Java language code. When you compile a Java code, the compilation is placed into bytecode. Bytecode is a platform-independent code, and you can run it on any machine with JVM installation. The JVM will interpret the bytecode and execute the Java program.

Java Application Types

Java technology is versatile and used to build various applications. This section will cover the different applications you can build with Java programming.

Desktop Applications

You can use Java to build desktop applications on Mac, Linux, and Windows servers. A desktop application can only be used on computer devices and is inaccessible from a browser. Also, desktop apps process words, edit images and can calculate spreadsheets.

You can build desktop apps using the Abstract Window Toolkit (AWT), Core Java, MySQL, and Swing.  Also, you can create a user-friendly interface for your app using text fields, menus, and buttons.

Web Applications

A web application operates on a remote web server and is delivered over the internet using a browser interface. Internet users can use web apps to play games online, interact with family, friends, and colleagues on social media networks, and shop in online stores.

You use Servlets and JavaServer Pages (JSP) to build web applications. Servlets are Java classes for handling HTTP requests and generating HTTP responses. On the other hand, JSPs are web pages that contain Java code to create dynamic content.

Mobile Applications

You can use Java to build mobile apps for Android devices. Android is an open-source operating system based on the Linux kernel and is used primarily for mobile phones. The Android SDK is a Java library set for mobile applications, and its features include UI components, multimedia support, and location-based services. These features make it easy to build mobile applications efficiently.

Enterprise Applications

Enterprise apps use software that integrates computer systems that run every phase of a company’s operations. Enterprise applications handle customer relationship, inventory, and human resource management.

You can build enterprise apps with the Java library set Enterprise JavaBeans (EJB). Also, EJB has server-side components for Java web security, transaction management, and persistence services.

Game Development

You can create games for mobile and desktop devices with Java Game Development Frameworks (JGDF). With JDF, you get audio support, can render graphics, and handle inputs.

Also, you can use Java to develop game engines, that is, software frameworks with a set of reusable components for building games. Artificial intelligence, scripting support, and physics simulation are notable game engine features that make it more effortless to create complicated games.

Java Syntax

Java Syntax consists of the language, the primary rules, commons, and constructions for creating programs the compiler and the computer understand. Generally, a standard programming language uses syntax and human language. Java syntax is similar to the programming codes, C++ and C#.

Also, Java programs have classes and methods. You can use a class as the blueprint to design objects, but a method is a pool of statements that execute a distinctive task. When creating Java files, they must be in text format with the ‘java’ extension.

Variables and Data Types

You can use variables to store data in a Java program, and you must declare a variable before using it. Also, variables are expressed with a data type, and you must indicate the data type the variable can hold. The following are the different Java built-in data types:

• byte: 8-bit integer
• short: 16-bit integer
• int: 32-bit integer
• long: 64-bit integer
• float: 32-bit floating-point number
• double: 64-bit floating-point number
• boolean: true or false
• char: single character

Below is how you can declare and use a variable in Java.

i
nt x = 5;
int y = 10;
int z = x + y;System.out.println(z); // Output: 15

The above example shows three variables of type int: x, y, and z. The values 5 and 10 are assigned to x and y, respectively. Then x and y are added and the result is assigned to z. Finally, the value of z (15) is oriented to the console.

Control Flow Statements

Developers use control flow statements to manage a Java program flow. Examples are if-else statements, while loops, do-while loops, for loops, and switch statements.

Below is how you can use an if-else statement in Java.

int x = 5;
if (x > 10) {
System.out.println("x is greater than 10");
} else {
System.out.println("x is less than or equal to 10"); }

In the above, the if-else statement determines whether the value of x is greater than 10. If it is, print the message ‘x is greater than 10’ to the console. Vice-versa.

Learn Java Basic Concepts

Another Java basic for beginners is learning the basic Java concepts. These concepts are essential for any beginner and you will find them in most Java programming courses. When you understand the fundamentals of programming, you will create efficient and robust apps.

Below are some of the basic Java concepts for beginners.

Object-Oriented Programming (OOP) Concepts

Object-oriented programming is a computer programming model that organizes software design around objects or data, instead of logic and function. Summarily, OOP uses objects to represent data and functionality. Also, objects are examples of class, and class is the template for creating objects.

The following are the OOP concepts supported by Java:

Encapsulation

Encapsulation is a process that joins data and code in a single unit and keeps them safe from outside interference and misuse. As a result, data is protected from third parties, and there’s controlled access to it.

Developers achieve encapsulation by declaring variables as private and providing public getter and setter methods for modifying and viewing the variables. Additionally, encapsulation promotes modularity and increases code reusability by making it easier to break large programs into smaller components.

Inheritance

In inheritance, one object inherits and acquires another object’s properties and methods, and it supports hierarchical classification. As a result, you can reuse codes and create specialized classes with similar characteristics. Also, with inheritance, you can effectively create more specific subclasses.

Polymorphism

Polymorphism is a process that performs a singular action in different ways, and it is a fundamental part of OOP. Although objects take different forms under polymorphism, they have the same interface, which can be used interchangeably. As a result, it is easier to write codes that can handle different objects and have a consistent design pattern.

Exception Handling

Exception handling involves detecting and handling errors in a Java program. An exception is thrown when there’s an error with a code, and the Java program catches and handles it. There are several built-in exception classes, like ArithmeticException, NullPointerException, and ArrayIndexOutofBoundsException.

Below is an example of how you can catch an exception in Java.

int x = 5;
int y = 0;
try {
int z = x / y;
System.out.println(z);
} catch (ArithmeticException e) {
System.out.println("Cannot divide by zero");
}

In the above example, the x variable is divided by zero, resulting in an ArithmeticException. Then, we used a try-catch block to detect the exception and print a message to the console. This prevents the program from crashing.

Simple Java Programs for Beginners

The following are simple Java programs for beginners:

Hello World Program

As taught in any Java tutorial for complete beginners, Hello World is the most basic programming language. When the code is entered, it prints ‘Hello World’ on the screen.

Here is an example:

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

Add Two Numbers Program

This Java program uses two integers as input and adds them together. It then prints the result on the screen.

Here is an example:

import java.util.Scanner;
public class AddTwoNumbers {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the first number: ");
int num1 = scanner.nextInt();
System.out.print("Enter the second number: ");
int num2 = scanner.nextInt();
int sum = num1 + num2;
System.out.println("The sum is: " + sum);
}
}

Even or Odd Program

The program takes an integer imputed by the user, checks if it is even or odd, and prints the result on the screen.

Here is an example:

import java.util.Scanner;
public class EvenOrOdd {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int num = scanner.nextInt();
if(num % 2 == 0) {
System.out.println(num + " is even.");
} else {
System.out.println(num + " is odd.");
}
}
}

Fibonacci Series Program

This program prints the Fibonacci series up to a specified number of terms.

import java.util.Scanner;
public class FibonacciSeries {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the number of terms: ");
int numTerms = scanner.nextInt();
int num1 = 0, num2 = 1, nextTerm;
System.out.print(num1 + " " + num2 + " ");
for(int i = 3; i <= numTerms; i++) {
nextTerm = num1 + num2;
System.out.print(nextTerm + " ");
num1 = num2;
num2 = nextTerm;
}
}
}

Factorial Program

The program calculates the factorial of a number.

import java.util.Scanner;
public class Factorial {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int num = scanner.nextInt();
int factorial = 1;
for(int i = 1; i <= num; i++) {
factorial *= i;
}
System.out.println("The factorial of " + num + " is " + factorial);
}
}

These are basic Java programs any beginner can try. Although you can start with them, don’t stop learning until you can build more complex and sophisticated programs.

Conclusion

This article covered how to learn Java for beginners and the different Java application types. You can start writing code once you learn Java basic concepts and master the Java programs for beginners. However, don’t stop learning; take an online Java course for advanced programs. Also, you can get more information on Java and web hosting on HostAdvice.

Next Steps: What Now?

• Web Hosting for Applications
• Top Best Java Hosting Providers for 2023
• A Beginners Guide to Web Hosting
• What is Cloud Hosting?

Further Reading – Useful Resources

• Is Java and Javascript the Same? Breaking Down the Key Differences
• What Is Java Used For? Exploring the Top Applications of This Popular Language
• How To Host A Java Web Application On A Web Server
• What Is Tomcat: Unveiling The Power Of Java Web Applications
• Advanced Java Programming
• Learn Java: Tutorials for Beginners, Intermediate, and Advanced Programmers
• Analyses of Student Programming Errors in Java Programming Courses
• An Intelligent Assessment Tool for Students’ Java Submissions in Introductory Programming Courses