1Z0-829 Utilizing Java Object-Oriented Approach — All Questions With Answers

Refer to the exhibit.

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

And the command:

$ javac Main.java
$ java Main

Output:
Hello

Now consider this class in another file:

public class Sub extends Main {
    public static void main(String[] args) {
        System.out.println("World");
    }
}

Compiled and run:

$ java Sub

What is the output?

Refer to the exhibit.

```
-- SQL to create table
CREATE TABLE departments (
    dept_id INT PRIMARY KEY,
    dept_name VARCHAR(50)
);

-- Materialized view with refresh
CREATE MATERIALIZED VIEW dept_summary
REFRESH COMPLETE ON DEMAND
AS
SELECT dept_id, COUNT(*) AS emp_count
FROM employees
GROUP BY dept_id;

-- Query
SELECT * FROM dept_summary;
```

Refer to the exhibit.

```
-- Creating a PL/SQL function
CREATE OR REPLACE FUNCTION get_emp_name (p_emp_id NUMBER) RETURN VARCHAR2 IS
    v_name employees.last_name%TYPE;
BEGIN
    SELECT last_name INTO v_name FROM employees WHERE employee_id = p_emp_id;
    RETURN v_name;
END;
```

Refer to the exhibit.

sealed class Shape permits Circle, Square {
    abstract double area();
}

final class Circle extends Shape {
    double area() { return 0; }
}

non-sealed class Square extends Shape {
    double area() { return 0; }
}

class Triangle extends Shape { }

public class Outer {
    private int x = 10;
    class Inner {
        private int x = 20;
        void method() {
            int x = 30;
            System.out.println(x);
            System.out.println(this.x);
            System.out.println(Outer.this.x);
        }
    }
    public static void main(String[] args) {
        Outer.Inner inner = new Outer().new Inner();
        inner.method();
    }
}

abstract class Animal {
    abstract void sound();
}
interface Pet {
    default void play() { System.out.println("Playing"); }
}
class Dog extends Animal implements Pet {
    void sound() { System.out.println("Bark"); }
}
public class Test {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.sound();
        d.play();
    }
}

public class Singleton {
    private static volatile Singleton instance;
    private Singleton() {}
    public static Singleton getInstance() {
        if (instance == null) {
            synchronized (Singleton.class) {
                if (instance == null) {
                    instance = new Singleton();
                }
            }
        }
        return instance;
    }
}

sealed class Shape permits Circle, Rectangle {
    void draw() { System.out.println("Shape"); }
}
non-sealed class Circle extends Shape {
    void draw() { System.out.println("Circle"); }
}
final class Rectangle extends Shape {
    void draw() { System.out.println("Rectangle"); }
}
class Triangle extends Shape {  // Line 10
    void draw() { System.out.println("Triangle"); }
}

public record Point(int x, int y) {
    public Point {
        if (x < 0 || y < 0) {
            throw new IllegalArgumentException();
        }
    }
    public int x() { return x; }
    public int y() { return y; }
}
public class Test {
    public static void main(String[] args) {
        Point p1 = new Point(1, 2);
        Point p2 = new Point(1, 2);
        System.out.println(p1.equals(p2));
        System.out.println(p1.x() == p2.x());
    }
}