# First Java Program : Hello World

"Hello, World!" program in Java along with a detailed explanation of the code:

#### HelloWorld.java:

```java
public class HelloWorld {
    public static void main(String[] args) {
        // This is a comment. Comments are ignored by the compiler.
        // The next line prints "Hello, World!" to the console.
        System.out.println("Hello, World!");
    }
}
```

#### Explanation:

* **`public class HelloWorld {`**: In Java, every application begins with a class definition. In this case, we define a class named `HelloWorld`.
* **`public static void main(String[] args) {`**: This line defines the `main` method, which is the entry point of every Java application. When you run a Java program, it starts executing from the `main` method.
* **`// This is a comment.`**: Comments in Java start with `//`. Comments are ignored by the compiler and are used for providing explanations within the code.
* **`System.out.println("Hello, World!");`**: This line prints "Hello, World!" to the console. Let's break it down:
  * **`System.out`**: `System` is a pre-defined class in Java that provides access to the system, and `out` is an object of type `PrintStream` which is connected to the console.
  * **`println("Hello, World!");`**: `println` is a method of the `PrintStream` class used to print a line of text to the console. In this case, it prints "Hello, World!" followed by a new line.

When you run this Java program, it will output:

```
Hello, World!
```

Explanation of Execution:

1. The program starts executing from the `main` method.
2. The `System.out.println("Hello, World!");` statement is executed, printing "Hello, World!" to the console.
3. The program completes its execution, and the output is displayed.

This simple program demonstrates the basic structure of a Java application, including class definition, the `main` method, comments, and the `System.out.println` statement used for output.


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