Can an abstract class be a subclass?

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 .
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Can a subclass of an abstract class have its own methods?

You can implement your methods in your abstract class and so they wont need to be necessary implemented in your subclass. Be sure to remove the abstract keyword from the methods and add body to them (in the abstract class).
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Can a subclass of a non abstract class be abstract?

13.3. An abstract class can be used just like a non-abstract class except that you cannot use the new operator to create an instance from the abstract class. An abstract class can be extended. A subclass of a non-abstract superclass can be abstract.
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Can an abstract class be a superclass?

That is, we cannot explicitly construct an object using an abstract class, but we can use it to help construct an object from a subclass. We can treat an abstract class as a superclass and extend it; its subclasses can override some or all of its inherited abstract methods.
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Can an abstract class have a concrete subclass?

An abstract class can be instantiated either by a concrete subclass or by defining all the abstract method along with the new statement. It may or may not contain an abstract method. An abstract method is declared by abstract keyword, such methods cannot have a body.
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Abstract Classes and Methods - Learn Abstraction in Java



Can abstract class be inherited?

An abstract class cannot be inherited by structures. It can contains constructors or destructors. It can implement functions with non-Abstract methods.
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Can abstract class have constructor?

Like any other classes in Java, abstract classes can have constructors even when they are only called from their concrete subclasses.
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Can abstract classes 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 .
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Can abstract classes be used in multilevel inheritance?

Can abstract classes be used in multilevel inheritance? Explanation: The abstract classes can always be used in multilevel inheritance.
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Can abstract class have implementation?

An abstract class can have an abstract method without body and it can have methods with implementation also. abstract keyword is used to create a abstract class and method. Abstract class in java can't be instantiated.
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Can a subclass extend abstract class?

abstract class A has not any methods,subclass B extends A and not be declared abstract.
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Can interface extends abstract class?

Interface can't provide the implementation of an abstract class. Inheritance vs Abstraction: A Java interface can be implemented using the keyword “implements” and an abstract class can be extended using the keyword “extends”.
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Can abstract class have zero abstract methods?

Yes, we can declare an abstract class with no abstract methods in Java. An abstract class means that hiding the implementation and showing the function definition to the user.
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How many subclasses can an abstract class have?

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.
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How do you create a subclass of abstract class?

We cannot create objects of an abstract class. To implement features of an abstract class, we inherit subclasses from it and create objects of the subclass. A subclass must override all abstract methods of an abstract class. However, if the subclass is declared abstract, it's not mandatory to override abstract methods.
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Can abstract class have concrete methods?

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.
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Can we achieve multiple inheritance using abstract class in Java?

In ABSTRACT class,we can't extends multiple abstract classes at a time. but In INTERFACE, we can implements multiple interfaces at time. Therefore , interfaces are used to achieve multiple inheritance in java. Nope.
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Can we extend multiple abstract class in Java?

A: Java has a rule that a class can extend only one abstract class, but can implement multiple interfaces (fully abstract classes).
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Can we declare a class as static?

So, Yes, you can declare a class static in Java, provided the class is inside a top-level class. Such clauses are also known as nested classes and they can be declared static, but if you are thinking to make a top-level class static in Java, then it's not allowed.
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Can constructor be inherited?

Constructors are not members, so they are not inherited by subclasses, but the constructor of the superclass can be invoked from the subclass.
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Can we declare interface method as static?

No, we cannot declare interface methods as static because static methods can not be overridden.
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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.
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Can abstract class have static methods?

If you declare a method in a class abstract to use it, you must override this method in the subclass. But, overriding is not possible with static methods. Therefore, an abstract method cannot be static.
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Can constructor be static?

A static constructor is used to initialize any static data, or to perform a particular action that needs to be performed only once. It is called automatically before the first instance is created or any static members are referenced.
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