Can an object subclass another object?

Can an object be a subclass of another object? A. Yes—as long as single inheritance is followed.

Can a subclass create a superclass object?

Assigning subclass object to a superclass variable

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 we create object in subclass?

If there are methods present in super class, but overridden by subclass, and if object of subclass is created, then whatever reference we use(either subclass or superclass), it will always be the overridden method in subclass that will be executed.

Can a subclass inherit multiple classes?

3.1.

A class can inherit another class and define additional members. We can now say that the ArmoredCar class is a subclass of Car, and the latter is a superclass of ArmoredCar. Classes in Java support single inheritance; the ArmoredCar class can't extend multiple classes.

Does a subclass inherit methods?

Default are not inherited. Any class from the same package can see default visibility methods. If the subclass is in the same package, then yes, otherwise no. ClassA can use ClassB's default methods only if they are in the same package.

28 Java | How Super class reference subclass object in java using inheritance | by Sanjay Gupta

Does a subclass need to have a constructor?

A subclass needs a constructor if the superclass does not have a default constructor (or has one that is not accessible to the subclass). If the subclass has no constructor at all, the compiler will automatically create a public constructor that simply calls through to the default constructor of the superclass.

What does a subclass inherit?

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: class Animal { float weight ; ...

Can a class be a subclass of 2 classes?

No, you can't.

Can an object belong to multiple classes?

An object can have multiple types: the type of its own class and the types of all the interfaces that the class implements. This means that if a variable is declared to be the type of an interface, then its value can reference any object that is instantiated from any class that implements the interface.

Does a subclass inherit both fields and methods?

A subclass inherits all the members (fields, methods, and nested classes) from its superclass. Constructors are not members, so they are not inherited by subclasses, but the constructor of the superclass can be invoked from the subclass.

Is a superclass object a subclass object?

ANS: b. A superclass object is a subclass object.

Can a superclass access subclass member?

Does a superclass have access to the members of a subclass? Does a subclass have access to the members of a superclass? No, a superclass has no knowledge of its subclasses.

Can we pass an object of a subclass to a method expecting an object of the super class?

Answer: Yes, you can pass that because subclass and superclass are related to each other by Inheritance which provides IS-A property.

Can we achieve abstraction without encapsulation?

The object is the abstract form of the real-world and its details are hidden using encapsulation. Thus encapsulation is required for abstraction.

Can we inherit constructor in Java?

No, constructors cannot be inherited in Java. In inheritance sub class inherits the members of a super class except constructors. In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.

Can we assign the parent class object to the subclass as a reference?

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 an image have two classes?

It is possible to assign an object two or more classes at the same time. Wordpress does this out of the box for images, for example. We used color coding of each class to detail each class applied to the image tag. To add multiple classes, simply separate each class with a space (not a comma).

Can two classes inherit from each other?

No, it is not possible. One of the reasons is stated below. In inheritance, if we create an object to child class, the base class constructor is by default called in derived class constructor as the first statement. Since there is cyclic dependency it will go into infinite loop.

What is the difference between super and subclass?

Summary – Superclass vs Subclass

The difference between the Superclass and Subclass is that Superclass is the existing class from which new classes are derived while Subclass is the new class that inherits the properties and methods of the Superclass.

Can a subclass extend two superclasses?

In some programming languages, like C++, it is possible for a subclass to inherit from multiple superclasses (multiple inheritance). Since multiple inheritance can create some weird problems, if e.g. the superclasses contain methods with the same names and parameters, multiple inheritance was left out in Java.

Can subclass access private members?

No, private fields are not inherited. The only reason is that subclass can not access them directly.

Does a subclass inherit constructors?

No a subclass cannot inherit the constructors of its superclass. Constructors are special function members of a class in that they are not inherited by the subclass. Constructors are used to give a valid state for an object at creation.

Can subclass override the methods of superclass?

A subclass within the same package as the instance's superclass can override any superclass method that is not declared private or final. A subclass in a different package can only override the non-final methods declared public or protected.

Do subclasses need __ init __?

If, as is common, SubClass actually does want to have all of BaseClass 's invariants set up before it goes on to do its own customisation, then yes you can just call BaseClass. __init__() (or use super , but that's complicated and has its own problems sometimes). But you don't have to.

Can a child class have a constructor?

A constructor cannot be called as a method. It is called when object of the class is created so it does not make sense of creating child class object using parent class constructor notation.