Inheritance limitations in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a key limitation of inheritance regarding multiple parent classes in Java?

Java does not support multiple inheritance with classes, meaning a class cannot inherit from more than one class directly. This avoids complexity and ambiguity.

intermediate

Why can inheritance lead to tight coupling between classes?

Because the child class depends heavily on the parent class's implementation, changes in the parent can affect the child, making the system less flexible.

beginner

Can private members of a parent class be accessed directly by a child class in Java?

No, private members are not accessible directly by child classes. They are hidden and can only be accessed through public or protected methods.

advanced

What problem does the 'diamond problem' illustrate in inheritance?

The diamond problem occurs when a class inherits from two classes that both inherit from the same superclass, causing ambiguity about which superclass method to use. Java avoids this by disallowing multiple class inheritance.

intermediate

How does Java allow multiple inheritance of behavior despite class inheritance limitations?

Java allows a class to implement multiple interfaces, which lets it inherit method signatures from many sources without inheriting implementation, avoiding multiple inheritance issues.

Which of the following is NOT allowed in Java inheritance?

A A class inheriting from multiple classes

B A class inheriting from one class

C A class implementing multiple interfaces

D A class overriding a parent method

Java does not support multiple inheritance with classes to avoid ambiguity and complexity.

Can a child class access private fields of its parent class directly?

A Only through public or protected methods

B No, never

C Only if the child class is in the same package

D Yes, always

Private fields are hidden from child classes but can be accessed via public or protected methods.

What does tight coupling in inheritance mean?

A Child classes are independent of parent classes

B Child classes depend heavily on parent classes

C Parent classes depend on child classes

D Classes have no relationship

Tight coupling means child classes rely strongly on parent classes, making changes risky.

How does Java avoid the diamond problem?

A By using abstract classes only

B By allowing multiple inheritance

C By using private inheritance

D By disallowing multiple class inheritance

Java avoids the diamond problem by not allowing a class to inherit from more than one class.

What feature allows Java to have multiple inheritance of behavior?

A Multiple class inheritance

B Abstract classes

C Interfaces

D Static methods

Interfaces let a class inherit method signatures from multiple sources without implementation conflicts.

Explain the main limitations of inheritance in Java and how Java addresses them.

Think about what Java allows and disallows in class relationships.

Describe the diamond problem and why it is important in understanding inheritance limitations.

Consider how multiple inheritance can confuse which method to use.