Guide to the Java Programming Language

What is Java?

Java is a general-purpose, object-oriented, class-based programming language with few implementation dependencies, which has made it a prolific computing platform used to create applications. As a result, Java is lightning-fast, safe, and dependable. It is widely used in laptops, game consoles, supercomputers, cell phones, and other devices for app development.

Now that we know what Java is, let's look at why it is one of the most trusted languages among developers.

What is the History of the Java Programming Language?

James Gosling, the "Father of Java," created Java in 1995. The project was initiated in the early 1990s by James Gosling and his team members. The idea was to create a "Simple, Robust, Portable, Platform-independent, Secured, High Performance, Multithreaded, Architecture Neutral, Object-Oriented, Interpreted, and Dynamic" programming language originally intended for interactive television. 

However, the technology was too sophisticated for the digital cable television business, and thus Java was born. It was, nevertheless, best suited for internet programming. Netscape later added Java technology.

Why Java?

There are countless reasons why Java is one of the most popular object oriented language for development. Let's look at some of the best features of Java that make it so popular!

• Easy to Learn: Because Java has an English-like syntax, it is ideal for novices who can learn Java in two stages: Core Java and Advanced Java. As a result, Java has a straightforward learning curve.
• Durable, Versatile, Cross Compatible: Java has long been the go-to object oriented language for creating web pages, browser extensions, mobile apps, and software tools such as Eclipse, IntelliJ IDEA, NetBeans IDE, and others. Because Java includes high-level concurrency tools and packages that allow for creating highly scalable solutions, developers and programmers prefer it for creating data science, data analytics, machine learning, and IoT applications.
• Rich API: Although Java has approximately fifty keywords, its Application Programming Interface (API) is vast and comprehensive - it is packed with several methods that may be used directly in any code. The Java API has methods for almost any purpose, such as networking, data and package management, connecting databases, processing XML, handling input-output, static memory management, etc.
• Excellent Community and Support: Java's active and supportive community is one of the key reasons for its success. It describes itself as the second-largest Stack Overflow community with many programmers around the world, including San Francisco, California. So, if you ever get stuck in a programming rut, you can rely upon thousands of online tutorials or message the Java community to help you. Java gives real-time answers and assists organizations around the world in resolving technical challenges through communities like Oracle or Java.
• Exceptional Documentation: Java is a free, open-source language with thousands of online tutorials, examples, and comprehensive documentation. It includes a comprehensive documentation that will assist you in resolving any issues you may experience when writing Java code for your web page or android application. 
• Excellent development tools: One of Java's most exciting aspects is the Integrated Development Environment (IDE). The free Java IDE includes many automation tools, editors, and debuggers. NetBeans, Eclipse, and IntelliJ IDEA are the three most popular Java IDEs for creating mobile apps and Java applications.

As a result of this, many companies look to hire skilled Java developers.

What Does a Java Developer Do?

A Java Developer is a programmer who creates, maintains, and manages Java-based software and mobile applications. A Java developer job is one of the most sought-after positions today, with most large firms employing Java to construct software systems and backend services.

Like other high-level programming languages, a Java developer r is responsible for many tasks throughout the application development lifecycle, from reference design and defined concepts to testing. Their responsibilities will vary substantially based on the company and work position. Here are some typical tasks Java developers may have:

• Java application phases include document, design, implementation, and maintenance.
• Participate in software and architectural development.
• Analysis, programming, testing, and debugging of operating systems, Java source file, and software.
• Catch difficulties with production and non-production applications.
• Changing Java classes and requirements into conditions.
• Collaborate with other programmers around the world.
• Create, test, deploy, and support application software.
• Suggest changes to improve existing Java application processes.
• Create technical Java classes and designs for app development.
• Create Java software application code.
• Create program tutorials and example programs for others to follow.
• Catch and suggest areas to improve in an application and package development.

Although Java has lost some of its popularity in recent years, the fact that significant organizations continue to use it demonstrates its dependability and solid support. As a result, the programming language has always had strong positions in industrial programming and the corporate area.

How to Become a Java Developer

In 2023, Java remains one of the most used programming languages. Moreover, because Java engineers are highly trained and have a wide range of duties, they can earn a solid living. Therefore, if you wish to become a Java developer, you must first learn some fundamental abilities. This includes:

• Enhancing Your Java Development Abilities: As a Java Developer, you will need to write code from the ground up for various web and non-web-based applications. So, you will also need a strong grasp of JavaScript, its syntax, and its concepts. In addition, you will also need a good understanding of HTML concepts. This means you'll have to learn Java and use it to build new projects, upgrades, and bug fixes. Learn about static methods, parameters and packages, JavaScript and Java Exception in web development and try building same name example projects with more info, tutorials, and examples.
• Mastering the Core Java SE: Begin by learning as much as you can about Oracle and Core Java (Java SE). You should be comfortable with fundamental concepts such as data, HTML, browser, string, loops, arrays, and operators. Furthermore, you should have a basic comprehension of JavaScript and of the Java SE general-purpose APIs, such as HTTP requests, Java.lang, Java.io, and Java.math.
• Learning Java EE: After finishing Core Java, begin learning Advanced Java, often known as Java EE (Enterprise Edition). Beginning with Java EE, you can focus on web development and start an introduction to android development using tutorials, example codes, and reference projects to become a proficient Java programmer.
• Improving Your Java Project Management Skills: You should start working on your project management abilities while you learn Java. Concentrate on planning, designing, and building small-scale Java projects during this stage. At this point, you should also be comfortable with Oracle. Managing small projects will aid in the development of your system architecture and management abilities.
• Learning Hibernate and Spring Frameworks: After completing Java SE and Java EE, you must master Java frameworks such as the Spring framework and the Hibernate framework. These are the most commonly used Java frameworks. In truth, most Java development firms today employ Spring frameworks like Spring Cloud, Spring Boot, and Spring MVC to create online apps.

Advantages of Writing Java Code

Efficient Memory Allocation

Java has an efficient memory allocation approach because it separates memory into two parts: heap and stack. The JVM allocates memory for any variable from the heap or stack area. When we declare a variable, the JVM allocates memory from the stack or the heap.

Flexible

Java is an object-oriented programming language that allows us to increase the code's flexibility and reusability. We can reuse the object in different programs by using the OOPs idea. It also improves security by integrating data and functions into a single unit inaccessible to the outside world. It also helps to break down huge modules into smaller ones, making them easier to understand.

Secure

By limiting explicit references, Java reduces security vulnerabilities and dangers. In many programming languages, a pointer stores the memory address of another value, which may result in unauthorized memory access. This issue is solved by eliminating the concept of pointers. In Java, a Security manager for each application allows us to set class access limitations.

Portable

Because of its platform independence, Java is a portable language. Because Java code may operate on any platform, it is portable and can be taken to and executed on any platform.

Automatic Garbage Collection

Java has automatic memory management, managed by the Java Virtual Machine (JVM). When programs no longer utilize objects, they do not refer to anything and do not need to be dereferenced or destroyed explicitly. Java automatically removes unneeded objects using the automated Garbage Collection procedure.

Supports Multithreading

Java is a multithreaded language, which means that multiple threads can run at the same time. A thread is a process's smallest unit. Multithreading allows us to get the most out of the CPU. Multiple threads share the same memory space, increasing the application's efficiency and performance. In addition, these threads operate independently and do not affect one another.

How to Install Java?

Download Java for Windows

If you wish to install Java, it is recommended that you get the most recent Java Development Kit installation exe for Windows for the newest features and bug fixes. Next, go to the Oracle Java Downloads website using your web browser. Then, click the x64 Installer download link under the Windows section on the Downloads page.

Install Java on Windows

1. To begin the installation, double-click the downloaded file. The installation wizard welcome screen appears when the installation file is run.
2. To move on to the next step, click Next. Specify a location for the Java installation files or use the default location and click next.
3. As soon as the wizard has completed the installation, the message "Successfully Installed" should show. Click "Close" to close the installation wizard.

Set Environmental Variables in Java

To enable program compilation from any directory, set the Java environment variables. Follow these steps to do that:

1. Open up Start Menu and Search for environment variables.
2. Choose the option to edit the system environment variables.
3. Select the Advanced tab on the System Properties box, and select Environment Variable.
4. Select the path variable under the System variables heading, then click Edit.
5. Put the path to the Java bin directory in the New box by clicking the New button.
6. To save the changes and close the variable editing window, click OK.

Confirm Successful Installation

To verify that Java is correctly installed, enter the following command at the command prompt:

java --version 

Components of Java

Java platform is a piece of software or a group of tools that enables us to run Java-coded applications. It consists of several components.

Java Compiler

Its job is to create Java class files from the Java source code. This is a compiler for the Java programming language. Platform-independent Java byte code can be found in Java class files.

After producing class files, JVM loads these class files and either interprets the generated bytecode or uses a Just-in-time (JIT) compiler to translate them to machine code.

The Java Virtual Machine (JVM)

The heart of the Java programming language is the JVM. Bytes are transformed into machine-specific code by the JVM.

The JVM offers many features, for example, memory management, reference objects, security, and garbage collection. JVM is platform-independent, and we can modify its attributes using its Virtual interface. This interface is not machine- or operating-system-dependent.

Because JVM is platform-independent, we can write Java and HTML programs on one machine and run them on another (WORA – Write – Once – Run – Anywhere).

The RAM contains the JVM. Therefore, when a Java program is converted to a class file, the Java compiler must run the Java program.

The Java Runtime Environment (JRE)

The runtime environment needed to run a Java program and application is known by its acronym, JRE. JRE includes JVM, binaries, and other classes to run Java programs effectively.

As a part of JDK, JRE lacks the Java compiler, debugger, and other development tools. Therefore, you can install JRE separately if your Java apps were created elsewhere, and you only need to execute them on your computer. With that said, JDK installation is required to proceed with JRE, which is also the bare minimum requirement to run Java apps on your computer.

The Java Development Kit (JDK)

Any Java environment must have this as its fundamental element. Along with the Java compiler, Java debugger, and other fundamental classes, JDK includes the Java Runtime Environment (JRE). Because JDK includes the whole executable, binaries, and tools necessary to construct and debug a Java application, it is used for Java development.

We will have different JDK installers for each Operating system because JDK is a platform-specific piece of software.

Development Best Practices

Proper Commenting

Add proper comments to give overviews of your code. Try adding codes in a new line to make your code readable and provide additional information that cannot be understood from the code itself, as a variety of people with diverse levels of Java experience will read your work. The purpose of comments is to explain how your code works so that a quality assurance engineer, tester, or maintenance staff member who may need to be better versed in Java may read them.

// This comment is a block comment
System.out.println("Flexiple Java"); // Printing a sample String
System.out.println("Hello World"); // This is an inline comment
public int addition(int x, int y) {
	/* Return addition of two numbers */
	int result = x + y;
	return result;
}

Using Naming Conventions

You must be deliberate in managing the naming convention for your codes; you should do this even before writing the first line of code.

For example, naming conventions deal with appropriately naming a variable, constant, method, class, and interface, among other things.

It is a good practice to let the names you provide for the various identifiers (method, class, and variable) be self-explanatory, distinct, and pronounceable.

In addition, you must constantly ensure to write readable codes that are simple for people to understand.

public class MainClass{
/* What does the class do? */

    public void method{
    // Example Method here
    }

    public static void main{
    // Code to run here
    System.out.println("Hello World");
    }
}

Avoid Memory Leaks

Memory leaks typically harm software performance. This is because Java automatically manages memory, leaving little control in the hands of the programmers. However, you can still employ some industry standards to safeguard your application from memory leaks:

• Release database connections at all times after a query is finished.
• Use finally blocks as frequently as you can.
• Static table-stored release instances

For example, consider the program below:

public class StaticReferenceLeak {
  public static List ArrayOfNumbers= new ArrayList<>();
  public void addNumbers() {
    for (int i = 0; i < 20000; i++) {
      ArrayOfNumbers.add(i);
    }
  }
  public static void main(String[] args) throws Exception {

System.out.println("Hello World");
    for (int i = 0; i < 200000; i++) {
        (new StaticReferenceLeak()).addBatch();
        System.gc();
        Thread.sleep(1000);
    }
  }
}

The addNumbers method adds 20000 numbers to the ArrayOfNumbers collection. However, we never remove the static object in the public class in this example. Even though we created the StaticReferenceLeak object in the main method of the Java file, we did not have a variable declaration pointing to it. Thus, the garbage collector cannot clean up the memory. This creates a memory leak that must be avoided.

Avoid Redundant Initializations

Although it is a frequent practice, initializing member variables in a public class with values like 0, false, and null, is not recommended. In Java, these values are the member variables' default initialization values. Consequently, it is recommended against initializing member variables directly and to be mindful of their default initialization settings.

Class Members Should Be Private in every Java File:

It is the best programming practice for Java programmers to make class members private in a Java file. The only logical reason to do this is to show how important information encapsulation is for software development. Then these attributes can be accessed outside the class via getter and setters as illustrated in the code below:

class Student {
  // private
  private String name;
  private int age;
  public String getName() {
	return this.name;
  }
  public int getAge() {
	return this.age;
  }
  // assign name
  public void setName(String name) {
	this.name = name;
  }
 
  // assign age
  public void setAge(int age) {
	this.age = age;
  }
public static void main(String[] args) throws Exception {
  // You code here
System.out.println("Hello World!");
}
}