Java 17 for Absolute Beginners: A Complete Guide to Get Started with Java Programming

Want to start learning Java programming? This guide is just for you. We’ll cover the basics of Java 17 in simple language—no experience needed!

✅ What You’ll Learn:

What is Java?
Java 17 Features (for beginners)
Basic Syntax
Data Types
Operators
Conditionals
Loops
Functions (Methods)
Object-Oriented Programming (OOP)
New Java 17 features (Text blocks, Records)
Practice Program

📌 What is Java?

Java is:

✅ A popular and easy-to-learn language
✅ Platform-independent (write once, run anywhere)
✅ Object-oriented (based on real-world objects)
✅ Used for apps, websites, games, and more

Java 17 is the latest Long-Term Support (LTS) version, released in 2021.

1. Java 17 Basic Syntax

Every Java program has a class and a main() method.

public class HelloJava {

public static void main(String[] args) {

System.out.println("Hello, Java 17!");

}

🔹 Notes:

public class HelloJava: Class definition
public static void main: Program entry point
System.out.println: Print to console

🔢 2. Data Types in Java

Java has two categories of data types:

✔ Primitive Data Types:

Data Type	Size	Example
`int`	4 bytes	100
`float`	4 bytes	3.14f
`double`	8 bytes	3.14159
`char`	2 bytes	'A'
`boolean`	1 bit	true / false
`long`	8 bytes	123456L
`short`	2 bytes	32000
`byte`	1 byte	127

✔ Non-Primitive:

String, Arrays, Objects, etc.

String name = "John";

int[] numbers = {1, 2, 3};

3. Operators in Java

✔ Arithmetic: + - * / %

✔ Relational: == != > < >= <=

✔ Logical: && || !

4. Conditional Statements

➤ if-else:


int score = 85;

if (score >= 90) {
    System.out.println("Excellent!");
} else if (score >= 60) {
    System.out.println("Passed");
} else {
    System.out.println("Failed");
}

➤ switch (enhanced in Java 17):


String day = "MONDAY";

switch (day) {
    case "MONDAY" -> System.out.println("Start of the week");
    case "FRIDAY" -> System.out.println("Weekend is near!");
    default -> System.out.println("Regular day");
}

🔁 5. Loops in Java

Loop Type	When to Use
`for` loop	When the number of iterations is known
`while` loop	When you want to repeat code until a condition is false
`do-while` loop	Like `while`, but runs at least once
`for-each` loop	For looping through arrays or collections

➤ for loop:


for (int i = 1; i <= 5; i++) {
    System.out.println("Count: " + i);
}

➤ while loop:


int i = 1;
while (i <= 5) {
    System.out.println(i);
    i++;
}

➤ do-while loop:


int i = 1;
do {
    System.out.println(i);
    i++;
} while (i <= 5);
➤ for-each Loop (Enhanced for loop)
Used to iterate over arrays, lists, or collections.

public class ForEachExample {
    public static void main(String[] args) {
        String[] fruits = {"Apple", "Banana", "Mango"};

        for (String fruit : fruits) {
            System.out.println(fruit);
        }
    }
}

6. Functions (Methods)


public class Calculator {
    static int add(int a, int b) {
        return a + b;
    }

    public static void main(String[] args) {
        int sum = add(10, 20);
        System.out.println("Sum = " + sum);
    }
}

7. Object-Oriented Programming (OOP) in Java 17

Java uses classes and objects to model real-world things.

➤ Class & Object Example:


public class Animal {
    String name;

    void makeSound() {
        System.out.println(name + " makes a sound");
    }

    public static void main(String[] args) {
        Animal dog = new Animal();
        dog.name = "Dog";
        dog.makeSound();
    }
}

OOP Concepts:

Concept	Description
Class	Blueprint for objects
Object	Instance of a class
Inheritance	One class inherits another
Encapsulation	Hiding internal details using `private`
Polymorphism	Many forms: method overloading/overriding
Abstraction	Hide complex logic behind interfaces

8. Java 17 Features for Beginners

✔ Text Blocks (Multi-line Strings):


String html = """
    <html>
        <body>
            <h1>Hello, Java 17!</h1>
        </body>
    </html>
    """;

System.out.println(html);

✔ Records (Immutable Data Classes):


public record Person(String name, int age) {}

public class Main {
    public static void main(String[] args) {
        Person p = new Person("Alice", 25);
        System.out.println(p.name());
        System.out.println(p.age());
    }
}

9. Practice Program

public class Student {
    String name;
    int marks;

    void printResult() {
        System.out.println("Name: " + name);
        if (marks >= 50) {
            System.out.println("Status: Pass");
        } else {
            System.out.println("Status: Fail");
        }
    }

    public static void main(String[] args) {
        Student s = new Student();
        s.name = "Bob";
        s.marks = 65;
        s.printResult();
    }
}

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