Super keyword in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the super keyword in Java?

The <code>super</code> keyword is used to refer to the parent class of the current object. It helps access parent class methods, constructors, and variables.

beginner

How do you call a parent class constructor using <code>super</code>?

You call a parent class constructor by writing <code>super(arguments);</code> as the first line inside the child class constructor.

intermediate

Can <code>super</code> be used to access parent class variables if they are hidden by child class variables?

Yes, <code>super.variableName</code> accesses the parent class variable when the child class has a variable with the same name.

intermediate

What happens if you don't explicitly call <code>super()</code> in a child class constructor?

Java automatically inserts a call to the no-argument parent constructor super() if you don't call it explicitly. If the parent has no no-arg constructor, it causes a compile-time error.

beginner

Can super be used to call overridden methods in the parent class?

Yes, <code>super.methodName()</code> calls the parent class version of a method that is overridden in the child class.

What does super() do inside a child class constructor?

A Calls the child class constructor

B Creates a new object

C Calls a method named super

D Calls the parent class constructor

super() calls the parent class constructor to initialize the parent part of the object.

How do you access a parent class variable hidden by a child class variable?

A Use <code>super.variableName</code>

B Use <code>this.variableName</code>

C Use <code>parent.variableName</code>

D Use <code>variableName()</code>

super.variableName accesses the parent class variable when hidden by the child class.

If a parent class has no no-argument constructor, what happens if the child constructor does not call super() explicitly?

A Code compiles fine

B Code throws a runtime exception

C Code fails to compile

D Parent constructor is called automatically with arguments

Java inserts super() automatically if not called explicitly, so if no no-arg constructor exists, compilation fails.

Which of these can super NOT be used for?

A Creating new objects

B Accessing parent class variables

C Calling parent class methods

D Calling parent class constructors

super is for accessing parent class members, not for creating new objects.

How do you call a parent class method that is overridden in the child class?

A <code>this.methodName()</code>

B <code>super.methodName()</code>

C <code>parent.methodName()</code>

D <code>methodName()</code>

super.methodName() calls the parent class version of an overridden method.

Explain how the super keyword helps in constructor chaining in Java inheritance.

Think about how child and parent constructors work together.

Describe how super can be used to access hidden variables and overridden methods in a child class.

Consider when child class has same names as parent.