Quick Answer: How Do You Create An Abstract Class Constructor?

Can you use this () and super () both in a constructor?

Because if you use this() and super() together in a constructor it will give compile time error.

Because this() and super() must be the first executable statement.

If you write this() first than super() will become the second statement and vice-versa.

That’s why we can’t use this() and super() together..

Can we declare an interface as final?

If you make an interface final, you cannot implement its methods which defies the very purpose of the interfaces. Therefore, you cannot make an interface final in Java. Still if you try to do so, a compile time exception is generated saying “illegal combination of modifiers − interface and final”.

Can abstract class have parameterized constructor in Java?

Yes, we can define a parameterized constructor in an abstract class.

Can a constructor be final?

No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. … In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.

Can constructor be declared as private?

Yes, we can declare a constructor as private. If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.

Can abstract class have body?

Abstract methods cannot have a body; all they can have is a method signature as shown in the example above. Variables are not allowed in interface. Hence any data declaration is ‘ public static final ‘; hence only constants. Interfaces can extend other interfaces ( one or more ) but not classes ( abstract or not ).

Can we override static method?

Can we Override static methods in java? We can declare static methods with the same signature in the subclass, but it is not considered overriding as there won’t be any run-time polymorphism. Hence the answer is ‘No’.

Can we create constructor in abstract class in C#?

Answer: Yes, an abstract class can have a constructor. In general, a class constructor is used to initialize fields. Along the same lines, an abstract class constructor is used to initialize fields of the abstract class.

Can an interface have a constructor?

No, you cannot have a constructor within an interface in Java. You can have only public, static, final variables and, public, abstract, methods as of Java7. From Java8 onwards interfaces allow default methods and static methods.

Can abstract class have constructor C++?

An abstract class can have constructor similar to normal class implementation. In the case of the destructor, we can declare a pure virtual destructor. It is important to have a destructor to delete the memory allocated for the class.

What is difference between abstract class and interface?

Classes can implement multiple interfaces, but only one abstract class. Abstract classes can contain non-abstract methods. They can both have methods, variables, and neither one can be instantiated. All variables declared in an interface are final, while an abstract class may contain non-final variables.

Why are constructors not part of the interface?

Constructor in an interface An Interface in Java doesn’t have a constructor because all data members in interfaces are public static final by default, they are constants (assign the values at the time of declaration). There are no data members in an interface to initialize them through the constructor.

Why does an abstract class have a constructor?

The main purpose of the constructor is to initialize the newly created object. In abstract class, we have an instance variable, abstract methods, and non-abstract methods. … The constructor inside the abstract class can only be called during constructor chaining i.e. when we create an instance of sub-classes.

Why constructor is not overridden?

Constructor Overriding is never possible in Java. This is because, Constructor looks like a method but name should be as class name and no return value. Overriding means what we have declared in Super class, that exactly we have to declare in Sub class it is called Overriding.

Can constructor be static or final?

The static , final and abstract keywords are not meaningful for a constructor because: static members belong to a class, but the constructor is needed to create an object. An abstract class is a partially implemented class, which contains abstract methods to be implemented in child class.

Can a constructor be abstract?

You can’t have an abstract constructor, as abstract means you need to provide the implementation for that at some point of time in your subclass. But you cannot override constructor. There will be no point in having an abstract constructor : Since the constructor needs to be of the same name as of class.

Can static class have constructor?

in a static class. You can have a static constructor in a static class but you cannot have an instance constructor inside a static class.