2.1 Creating and Using Objects

• What are the three key concepts in object-oriented programming (OOP)?

  Encapsulation, inheritance, polymorphism
• What do public methods provide in encapsulation?

  Clear interface
• What type of structure does inheritance create in code organization?

  Hierarchical structure
• What is an object in object-oriented programming?

  Self-contained entity
• What defines the behavior of an object in OOP?

  Methods
• What is a class in object-oriented programming?

  Blueprint for objects
• Data hiding in encapsulation protects data from direct manipulation.

  True
• Inheritance avoids repetitive coding.


  True
• Method overloading allows a class to have multiple methods with the same name but different signatures.


  True
• The state of an object is defined by its properties or attributes.


  True
• The `new` keyword is used to create an object in OOP.


  True
• To create an object, you use the `new` keyword along with the class name and call the constructor
• Match the OOP concept with its description:

  Class ↔️ Blueprint for objects

  Object ↔️ Instance of a class

  Constructor ↔️ Method to initialize object state
• What does encapsulation aim to achieve in OOP?

  Data hiding
• Method overriding in polymorphism allows subclasses to customize inherited behavior.


  True
• What are the two components of an object in OOP?

  State and behavior
• If no constructor is defined, Java provides a default constructor.


  True
• What are attributes within an object used for?

  Hold the object's data
• The syntax for defining a method within a class starts with the access
• Mutator methods (setters) are used to modify the values of an object's attributes.


  True
• Methods operate on the object's data
• Match the method type with its purpose:

  Accessor (Getter) ↔️ Retrieve attribute values

  Mutator (Setter) ↔️ Modify attribute values
• What are methods within objects called?

  Behaviors or actions
• Mutator methods are also known as setters
• Steps involved in object-oriented programming (OOP):

  1️⃣ Organize code into objects

  2️⃣ Bundle data and methods

  3️⃣ Apply encapsulation

  4️⃣ Apply inheritance

  5️⃣ Apply polymorphism
• Polymorphism enables objects of different classes to be treated as objects of a common superclass
• What defines the properties or attributes of an object in OOP?

  State
• What keyword is used to create an object from a class?

  new
• What does a class define about an object?

  State and behavior
• A constructor is a special method within a class that initializes the object's state
• What are the parameters required for the parameterized constructor of the `Person` class?

  String name and int age
• What are the three attributes defined in the `Person` class example?

  String name, int age, Address address
• What are methods within objects called?

  Behaviors or actions
• A class is a blueprint or template for creating objects.


  True
• To create an object, you use the `new` keyword along with the class name and call the constructor
• Inheritance allows new classes to inherit properties and methods from existing ones, promoting code reuse
• In OOP, an object is a self-contained entity that bundles data and methods
• Object creation involves using the `new` keyword and a constructor.


  True
• Attributes define the state of an object by holding its data.


  True
• Why is it recommended to define constructors explicitly in Java?

  Ensures proper initialization