Why does an abstract class have a constructor?
Abstract classes require constructors to enforce a design contract using which objects can be initialized.
Constructor can be used to setting up an attribute of the base class.
This attribute will be available in subclass by inheritance.
Before using this attribute, using the constructor it can be initialized..
Can abstract class have constructor in CPP?
A class with one (or more) virtual pure functions is abstract, and it can’t be used to create a new object, so it doesn’t have a constructor.
Can abstract class be instantiated?
Abstract classes cannot be instantiated, but they can be subclassed. When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract .
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 body?
Abstract methods are declaration only and it will not have implementation. It will not have a method body. A Java class containing an abstract class must be declared as abstract class. An abstract method can only set a visibility modifier, one of public or protected.
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.