The canonical starting point in Java programming demonstrating standard console output.

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
        System.out.println("Welcome to Java 17 Online Compiler!");
    }
}

Demonstrates primitive types (int, double, boolean) and String objects.

public class Main {
    public static void main(String[] args) {
        int studentId = 101;
        double gradeAverage = 94.5;
        char letterGrade = 'A';
        boolean isEnrolled = true;
        String name = "Sarah Connor";
        
        System.out.printf("Student: %s (ID: %d)%n", name, studentId);
        System.out.printf("Grade: %c (%.1f%%)%n", letterGrade, gradeAverage);
        System.out.println("Active Enrollment: " + isEnrolled);
    }
}

Decision-making with standard if-else and Java 17 arrow-syntax switch expressions.

public class Main {
    public static void main(String[] args) {
        int score = 88;
        
        if (score >= 90) {
            System.out.println("Result: Grade A");
        } else if (score >= 80) {
            System.out.println("Result: Grade B");
        } else {
            System.out.println("Result: Grade C");
        }

        String day = "FRIDAY";
        String type = switch (day) {
            case "MONDAY", "FRIDAY" -> "Busy Weekday";
            case "SATURDAY", "SUNDAY" -> "Relaxing Weekend";
            default -> "Midweek Day";
        };
        System.out.println(day + " is a " + type);
    }
}

Iterating through numeric sequences and arrays with standard and enhanced for-each loops.

public class Main {
    public static void main(String[] args) {
        System.out.print("Counting 1 to 5: ");
        for (int i = 1; i <= 5; i++) {
            System.out.print(i + " ");
        }
        System.out.println();

        String[] frameworks = {"Spring Boot", "Quarkus", "Micronaut"};
        System.out.println("Java Frameworks:");
        for (String fw : frameworks) {
            System.out.println(" - " + fw);
        }
    }
}

Encapsulation with private fields, parameterized constructor, and member methods.

class Account {
    private String owner;
    private double balance;

    public Account(String owner, double initialDeposit) {
        this.owner = owner;
        this.balance = initialDeposit;
    }

    public void deposit(double amount) {
        this.balance += amount;
    }

    public void display() {
        System.out.printf("%s's Balance: $%.2f%n", owner, balance);
    }
}

public class Main {
    public static void main(String[] args) {
        Account acc = new Account("Alice", 1500.00);
        acc.deposit(350.50);
        acc.display();
    }
}

Dynamic resizing and sorting using ArrayList and Collections.sort().

import java.util.ArrayList;
import java.util.Collections;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> languages = new ArrayList<>();
        languages.add("Java");
        languages.add("Python");
        languages.add("C++");
        languages.add("Rust");

        Collections.sort(languages);
        System.out.println("Sorted Languages: " + languages);
        System.out.println("Total Count: " + languages.size());
    }
}