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Java Hello World

Introduction to Java Programming Language.

Java is a high-level, robust, and platform-independent programming language. It was developed by James Gosling and his team at Sun Microsystems in the mid-1990s. Java is widely used for developing a variety of applications, including web, desktop, mobile, and enterprise applications.

History​

Java was originally created to support interactive television, but it soon became clear that it had potential for use in other areas as well. Sun Microsystems released Java publicly in 1995, and it quickly gained popularity due to its simplicity, security, and versatility.

One of the key features that contributed to Java's success was its "write once, run anywhere" (WORA) philosophy. This means that Java programs can be written on one platform and run on any other platform that has a Java Virtual Machine (JVM) installed. This portability made Java an attractive choice for developers.

Over the years, Java has evolved and gained new features and enhancements. It is now maintained and developed by Oracle Corporation after their acquisition of Sun Microsystems in 2010.

Features​

Java offers a wide range of features that make it a powerful and versatile programming language:

  1. Object-Oriented: Java is a fully object-oriented language, which means everything in Java is an object. It supports encapsulation, inheritance, polymorphism, and other object-oriented principles.

  2. Platform-Independent: Java programs are compiled into bytecode, which can run on any platform that has a JVM. This makes Java highly portable and enables the "write once, run anywhere" capability.

  3. Garbage Collection: Java's garbage collector automatically manages memory allocation and deallocation, freeing developers from manual memory management. This makes Java programs more robust and less prone to memory errors.

  4. Exception Handling: Java has built-in support for exception handling, allowing developers to handle and recover from runtime errors gracefully.

  5. Multi-threading: Java provides built-in support for multi-threading, allowing developers to write concurrent and parallel programs easily.

  6. Security: Java's built-in security features, such as the Java Security Manager, help protect against unauthorized access and malicious activities.

  7. Rich Standard Library: Java comes with a vast standard library that provides a wide range of useful classes and methods for various programming tasks, such as networking, file I/O, database connectivity, and more.

Hello World Example​

Let's start with a simple "Hello World" example in Java. This will give you a basic understanding of how Java programs are written and executed.

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

In this example:

  • The public keyword indicates that the class is accessible from any other class.
  • The class keyword is used to declare a class in Java.
  • HelloWorld is the name of the class, which should match the filename (HelloWorld.java).
  • The main method is the entry point of a Java program. It is where the program starts execution.
  • String[] args is the parameter passed to the main method. It allows command-line arguments to be passed to the program.
  • System.out.println is used to print the "Hello, World!" message to the console.

To run the above program, you need to:

  1. Install the Java Development Kit (JDK) from the official Java website: https://www.oracle.com/java/technologies/javase-jdk14-downloads.html
  2. Open a text editor and copy the above code into a new file named HelloWorld.java.
  3. Open a command prompt or terminal and navigate to the directory where the HelloWorld.java file is located.
  4. Compile the Java source file using the javac command: javac HelloWorld.java
  5. Run the compiled Java program using the java command: java HelloWorld

You should see the output Hello, World! printed to the console.

Comparison with Other Languages​

Java has many similarities and differences compared to other programming languages. Here are some notable points of comparison:

  • C++: Java was heavily influenced by C++ but aimed to simplify and improve upon it. Java introduced automatic memory management, removed support for pointers, and added features like garbage collection and exception handling. Java also has a more extensive standard library compared to C++.

  • C#: C# is Microsoft's equivalent to Java. Both languages have similar syntax and features, but C# is primarily used for Windows development, while Java is platform-independent.

  • Python: Python is a dynamically-typed scripting language known for its simplicity and readability. Java, on the other hand, is statically typed and offers better performance. Java is commonly used for large-scale applications and enterprise development, while Python is popular for scripting, web development, and data analysis.

  • JavaScript: Despite the similar name, JavaScript and Java are different languages with distinct use cases. JavaScript is mainly used for client-side web development, whereas Java is a general-purpose language used for a wider range of applications.

For more information and official documentation, you can visit the official Java website: https://www.oracle.com/java/