Java Constructor Multiple Choice Questions: AP Exam Prep

📚 Quick Study Guide

• 🔑 A constructor initializes an object when it is created. It has the same name as the class.
• 🛠️ If you don't define a constructor, Java provides a default no-argument constructor.
• 🧮 Constructors can be overloaded, meaning you can have multiple constructors with different parameters.
• 📝 Constructors do not have a return type (not even `void`).
• 🔗 The `this` keyword can be used within a constructor to refer to the current object.
• ➡️ The `super()` keyword is used to call the constructor of the superclass. It must be the first statement in the constructor.
• 💡 A constructor can call another constructor in the same class using `this()`.

🧪 Practice Quiz

1. Which of the following statements about constructors is true?
   1. A. A constructor must have a return type.
   2. B. A constructor can have any name.
   3. C. A constructor is used to initialize objects.
   4. D. A constructor is automatically called when a class is declared.
2. What happens if you don't define a constructor in a class?
   1. A. The code will not compile.
   2. B. Java provides a default constructor.
   3. C. You must initialize all instance variables manually.
   4. D. An error will occur at runtime.
3. How can you call a constructor of the superclass from a subclass constructor?
   1. A. Using the `this()` keyword.
   2. B. Using the `super()` keyword.
   3. C. By directly calling the superclass constructor by name.
   4. D. It is not possible to call the superclass constructor.
4. What is constructor overloading?
   1. A. Having multiple constructors with the same parameters.
   2. B. Having multiple constructors with different parameters.
   3. C. Inheriting constructors from a superclass.
   4. D. Calling a constructor from another class.
5. Which keyword refers to the current object within a constructor?
   1. A. `object`
   2. B. `self`
   3. C. `this`
   4. D. `current`
6. What is the purpose of a constructor?
   1. A. To define the methods of a class.
   2. B. To allocate memory for an object.
   3. C. To initialize the state of an object.
   4. D. To destroy an object.
7. If a class has multiple constructors, how does Java know which one to call?
   1. A. Based on the order in which they are defined.
   2. B. Based on the number and types of arguments passed.
   3. C. Based on the return type of the constructor.
   4. D. Java randomly chooses a constructor to call.