Is it possible a link to a superclass assign a reference to an object of a subclass? Yes , it is. Let a superclass and a subclass be given. If you declare a reference to a superclass, then this reference can be assigned the value of a reference to a subclass that inherits this superclass.
Can a subclass reference refer to a superclass object?
No. It makes zero sense to allow that. The reason is because subclasses generally define additional behavior. If you could assign a superclass object to a subclass reference, you would run into problems at runtime when you try to access class members that don’t actually exist.
Can you use a subclass object in place of a superclass object?
a) You can always use a superclass object in place of a subclass object.
What is it called when I declare an object of a superclass and assign an object of a subclass to it?
Therefore, if you assign an object of the subclass to the reference variable of the superclass then the subclass object is converted into the type of superclass and this process is termed as widening (in terms of references) .
Can an object be a subclass of another object?
2. Can an object be a subclass of another object? A. Yes —as long as single inheritance is followed.
Can a superclass access subclass member?
Does a superclass have access to the members of a subclass? ... No, a superclass has no knowledge of its subclasses. Yes, a subclass has access to all nonprivate members of its superclass .
Can you cast a superclass to a subclass?
You can try to convert the super class variable
Can a superclass call a subclass method?
Yes its possible to call sub class methods using super class by type casting to sub class object .
What two methods from object are often overridden?
Of the 11 methods provided by Object, equals() and toString() are often overridden by subclasses. An object’s toString() method is called when the compiler must produce a string representation of the object, such as for a call to System.
What is one method from object that is often overridden?
One commonly overriden Object method is toString() , which is often used to print out the attributes of an object. It is a good idea to write your own toString() method in every class. In a subclass, toString() can call the superclass toString() method using super. toString() and then add on its own attributes.
What do you mean by nameless objects?
Explanation: The nameless objects are basically referred to as anonymous objects . The anonymous objects do not have any names. We can also say that, when an object is initialized but is not assigned to any reference variable, it is called an anonymous object.
Can we define subclass first and superclass later in a Java file?
Classes in Java exist in a hierarchy. A class in Java can be declared as a subclass of another class using the extends keyword . A subclass inherits variables and methods from its superclass and can use them as if they were declared within the subclass itself: ... A subclass can be further subclassed.
What happens if superclass and subclass having same field name?
what happens if both superclass and subclass have a field with same name? Sub class field will hide the Super class field . Hidden super class field in sub class can be accessed using super keyword.
Which members of superclass are not directly accessible in subclass?
The private members of the superclass cannot be inherited to the subclass because the private members of superclass are not available to the subclass directly. They are only available in their own class. 2. The default members of the parent class can be inherited to the derived class within the same package.
How do you cast an object to a string in Java?
We can convert Object to String in java using toString() method of Object class or String. valueOf(object) method . You can convert any object to String in java whether it is user-defined class, StringBuilder, StringBuffer or anything else.
Is hybrid inheritance supported in Java?
Since Java does not support multiple inheritance
