Question

Java I need help

Q1: Suppose this is a legal assignment statement: Student obj1 = new Book(); what is the relationship between Student and Book?

  
1 - Student has Book as a field

  
2 - Student is a subtype of Book

  
3 - No Relationship

  
4 - Book is a subtype of Student.

Question2:

Q2: What are the types involved in this statement: Vehicle v1 = new Car();

  
1- Car

  
2- new

  
3- Vehicle and Car

  
4- v1

Q3: If two or more classes share a lot of data and behavior then the typical solution to minimize code duplication is ______________________

  
1- Encapsulation

  
2- to leave as to avoid errors

  
3- Inheritance

  
4- Defining new methods in each

Q4: If a method in a superclass has no obvious implementation then we define it as ___________

  
1- protected

  
2- static

  
3- private

  
4- abstract

Q5: _________ is a mechanism by which a call to an overridden method is resolved at run-time.

  
1- Static Binding

  
2- Call by Value

  
3- Dynamic Method Lookup

  
4- Method Overloading

Q6: When you let an object call a method to do something without knowing how that method is implemented then the process is called

1- Abstraction & object delegation

  

2- Polymorphism

  
3- Inheritance

  
4- Substitution

Q-7 Suppose we have Computer, Labtop and Desktop as classes. What is a sensible way to relate them to each other?

  
1- Computer should have Laptop and Desktop as fields

  

2- Laptop and Desktop should be subclasses of Computer

  

3- All classes should be independent of each other

  

4- Laptop and Desktop should have Computer as a field

Q8: Name the object dynamic types of car and v in these statements: Object car = new Car(); Vehicle v = new Truck();

  
1- Both are Vehicle

  
2- Both are Ineger

  
3- Car and Truck

  
4- Both are String

Q9: Assume that you see these lines of code:

Device dev = new Printer();

dev.getName();

Printer is a subclass of Device. which class must have a definition of act()for this code to compile?

  
1- Printer

  
2- String

  
3- Device

  
4- Dev

Q10: To call a superclass method foo() from a subclass we use the statement

  
1- foo().super;

  
2- super();

  
3- super.foo();

  
4- this;

Answer 1

Q1. 4-Book is a subtype of student

Q2. 1-Car

Q3. 3-Inheritance

Q4. 4-abstract

Q5. 3-Dynamic Method Lookup

Q6. 1-Abstraction & Object delegation

Q7. 2-Laptop and Desktop should be subclasses of Computer

Q8. 3-car and truck

Q9. 1-Printer

Q10. 3-super.foo()