Method overriding in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is method overriding in Java?

Method overriding occurs when a subclass provides its own version of a method that is already defined in its superclass. It allows the subclass to change or extend the behavior of that method.

intermediate

What are the rules for method overriding in Java?

The method in the subclass must have the same name, return type, and parameters as the method in the superclass. The overriding method cannot have more restrictive access than the overridden method.

beginner

Can a private method be overridden in Java?

No, private methods cannot be overridden because they are not visible to subclasses. They are only accessible within the class they are declared in.

beginner

What is the use of the @Override annotation?

The @Override annotation tells the compiler that the method is intended to override a method in the superclass. It helps catch errors if the method does not correctly override any method.

intermediate

What happens if you call an overridden method on a superclass reference pointing to a subclass object?

The subclass's version of the method is called. This is called dynamic method dispatch and supports runtime polymorphism.

Which of the following is true about method overriding?

A The subclass method must have the same signature as the superclass method.

B The subclass method can have a different return type than the superclass method.

C Private methods can be overridden.

D The subclass method must have more restrictive access than the superclass method.

Method overriding requires the subclass method to have the same name, parameters, and return type as the superclass method.

What does the @Override annotation do?

A It forces the method to be private.

B It changes the method's return type.

C It prevents the method from being overridden.

D It tells the compiler the method is intended to override a superclass method.

The @Override annotation helps the compiler check that the method correctly overrides a method from the superclass.

If a superclass reference points to a subclass object, which method is called when invoking an overridden method?

A The subclass method.

B Both methods are called.

C The superclass method.

D An error occurs.

Java uses dynamic method dispatch to call the subclass's overridden method at runtime.

Can a subclass override a static method from its superclass?

A Yes, static methods can be overridden.

B Only if the superclass method is public.

C No, static methods cannot be overridden but can be hidden.

D Only if the subclass method is also static.

Static methods belong to the class, not instances, so they cannot be overridden but can be hidden by a subclass static method.

Which access modifier is NOT allowed for an overriding method compared to the overridden method?

A Same restrictive

B More restrictive

C Less restrictive

D Public

The overriding method cannot have more restrictive access than the overridden method to maintain accessibility.

Explain method overriding and why it is useful in Java.

Think about how subclasses can change what a method does.

Describe the rules and restrictions when overriding a method in Java.

Focus on what must stay the same and what cannot be changed.