Java > Hello Java

Hello Java - First Program

The HelloJava program is a simple Java program that demonstrates the fundamental structure of a Java application. It includes key elements such as the package statement, comments, class definition, the main method, and executable statements.

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Program Structure

// Package declaration (if any)
package com.vvsk.fullstack;

// Import statements (if needed)

// Class definition
public class HelloJava {
    // Main method - Entry point of the Java program
    public static void main(String[] args) {
        // Print statement to display output
        System.out.println("Hello, Java!");
    }
}

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Explanation of Components

1. Package Statement

package com.vvsk.fullstack;

• A package is a namespace that organizes Java classes.
• The package statement (optional) must be the first line in the Java file.
• It helps in managing large-scale projects by grouping related classes.

2. Comments Section

// This is a single-line comment
/* This is a multi-line comment */

• Comments are ignored by the compiler and are used to explain code.
• Single-line comments (//) and multi-line comments (/* */) are commonly used.

3. Class Declaration

public class HelloJava {

• The class keyword is used to define a class.
• The class name must match the filename (HelloJava.java).
• public means the class is accessible from other parts of the program.

4. Main Method (PSVM - Public Static Void Main)

public static void main(String[] args) {

• The main method is the entry point of any Java application.
• public: The method is accessible to the JVM.
• static: It can run without creating an object of the class.
• void: It does not return any value.
• String[] args: It accepts command-line arguments.

5. Actual Code Statements inside main

System.out.println("Hello, Java!");

• System.out.println() prints the message to the console.
• "Hello, Java!" is the output displayed when the program runs.

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Output

Hello, Java!

This simple program introduces basic Java syntax and structure, setting the foundation for more advanced programming concepts.