Can abstract class extends non-abstract class?

A concrete class is a conventional term used to distinguish a class from an abstract class. And an abstract class cannot be instantiated, only extended. An abstract class can extend another abstract class. And any concrete subclasses must ensure that all abstract methods are implemented.

Can abstract class extends?

abstract classes can't be instantiated, only subclassed. other classes extend abstract classes. can have both abstract and concrete methods. similar to interfaces, but (1) can implement methods, (2) fields can have various access modifiers, and (3) subclasses can only extend one abstract class.

Can abstract class extend from a concrete class?

An abstract class can not extend a concrete class.

Can abstract class can have non-abstract methods?

An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed.

Can abstract class inherit non-abstract class?

An abstract class cannot be inherited by structures. It can contains constructors or destructors. It can implement functions with non-Abstract methods. It cannot support multiple inheritance.

Abstract Classes and Methods - Learn Abstraction in Java

Can you extend a non-abstract class?

Yes :) Unless it has the final modifier. Show activity on this post. No it doesn't need to have the word abstract, the word abstract just wont allow you to create an instance of that class directly, if you use the word abstract you can only create an instance of the classes that extend that abstract class.

Can we override final method of abstract class?

Declaring abstract method final

Similarly, you cannot override final methods in Java. But, in-case of abstract, you must override an abstract method to use it. Therefore, you cannot use abstract and final together before a method.

Can abstract class have final methods?

therefore, a final abstract combination is illegal for classes. Hence, a final class cannot contain abstract methods whereas an abstract class can contain a final method.

Can abstract class have all concrete methods?

No. Abstract class can have both an abstract as well as concrete methods. A concrete class can only have concrete methods. Even a single abstract method makes the class abstract.

Can we have non-abstract methods in an interface?

Type of methods: Interface can have only abstract methods. An abstract class can have abstract and non-abstract methods.

Can an abstract class extend an interface?

An abstract class can declare constructors and destructors. It can extend any number of interfaces. It can extend only one class or one abstract class at a time.

Can an abstract class inherit another class?

Yes, An Abstract class can inherit from a concrete class(non-Abstract class) and can also inherit from the following- According to inheritance concept in C#, an Abstract class can inherit from only one class either it can be Abstract or Concrete class but it can inherit from multiple interface.

Can a non-abstract class implement an interface?

Interfaces can not have non-abstract Methods while abstract Classes can. A Class can implement more than one Interface while it can extend only one Class.

Can abstract class have abstract child?

Yes you can do it. An abstract class can extend another non final class having at least one non private constructor.

Can static classes be extended?

Just like static members, a static nested class does not have access to the instance variables and methods of the outer class. You can extend static inner class with another inner class.

Can concrete class be extended?

A concrete class is complete in itself and can extend and can be extended by any class.

Can abstract class have private methods?

If a method of a class is private, you cannot access it outside the current class, not even from the child classes of it. But, incase of an abstract method, you cannot use it from the same class, you need to override it from subclass and use. Therefore, the abstract method cannot be private.

Can we declare 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.

Can interface be instantiated?

An interface can't be instantiated directly. Its members are implemented by any class or struct that implements the interface. A class or struct can implement multiple interfaces.

Can we declare constructor as final?

No, a constructor can't be made final. A final method cannot be overridden by any subclasses. As mentioned previously, the final modifier prevents a method from being modified in a subclass. The main intention of making a method final would be that the content of the method should not be changed by any outsider.

Can we override static method?

No, we cannot override static methods because method overriding is based on dynamic binding at runtime and the static methods are bonded using static binding at compile time. So, we cannot override static methods.

Can we declare interface method as static?

All methods in an interface are explicitly abstract and hence you cannot define them as static because static methods cannot be abstract.

Can we declare overloaded method as final?

Yes, overloading a final method is perfectly legitimate.

Can I declare static method as abstract Why?

A static method belongs to class not to object instance thus it cannot be overridden or implemented in a child class. So there is no use of making a static method as abstract.

Can we overload a final method?

Can We Override a Final Method? No, the Methods that are declared as final cannot be Overridden or hidden. For this very reason, a method must be declared as final only when we're sure that it is complete.