Can we declare abstract class as public?

Abstract classes are similar to interfaces. You cannot instantiate them, and they may contain a mix of methods declared with or without an implementation. However, with abstract classes, you can declare fields that are not static and final, and define public, protected, and private concrete methods.

Are abstract classes Public or private?

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.

Should an abstract class be public?

It depends on your use case. If you want the methods of the abstract class visible to instances of your derived class, you should make them public. If, on the other hand, you want the methods visible only to your derived class, you should make them protected.

Can we use public with abstract?

Only public & abstract are permitted in combination to method. Example: public abstract void sum(); We use abstract keyword on method because Abstract methods do not specify a body.

Can an abstract class be declared?

Abstract class can have static fields and static method, like other classes. An abstract class cannot be declared as final. Only abstract class can have abstract methods.

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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.

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 .

Can abstract class be protected?

And it can't be "some of them," since we would need a way of defining which classes can access it, which is what the visibility modifier was for in the first place. So for these reasons, top-level classes cannot be private or protected; they must be package-private or public.

Can we declare local inner class as abstract?

Yes, we can declare local inner class as abstract.

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.

Can we declare abstract method as protected?

The public abstract method will be accessible in the other package where as the protected abstract method can not be accessed. Check the example below. Another package which extends the class and implements the abstract class.

Can an abstract class have public abstract methods?

A Java class that is declared using the keyword abstract is called an abstract class. New instances cannot be created for an abstract class but it can be extended. An abstract class can have abstract methods and concrete methods or both.

Can abstract class be public in C#?

public abstract class A { // Class members here. } An abstract class cannot be instantiated. The purpose of an abstract class is to provide a common definition of a base class that multiple derived classes can share.

Can we declare constructor 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 private?

Abstract classes can have private methods. Interfaces can't. Abstract classes can have instance variables (these are inherited by child classes).

Can we declare interface methods as private?

Java 9 onwards, you can include private methods in interfaces. Before Java 9 it was not possible. In Java SE 7 or earlier versions, an interface can have only two things i.e. Constant variables and Abstract methods. These interface methods MUST be implemented by classes which choose to implement the interface.

Can we declare class as private in Java?

No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier).

Can abstract classes have static methods?

Yes, of course you can define the static method in abstract class. you can call that static method by using abstract class,or by using child class who extends the abstract class. Also you can able to call static method through child class instance/object.

Can we declare local inner classes as static?

Therefore, the declaration of method local inner class cannot use any access modifiers such as public, protected, private, and non-access modifiers such as static. Method local inner class in Java can also be declared inside the constructor, static initializers, and non-static initializers.

Can abstract class have final methods?

As a final class cannot be inherited. However, an abstract class can have a final method. This final method is treated like a normal method with a body which cannot be overridden.

Can abstract class extend concrete?

An abstract class can not extend a concrete class.

Is abstract Cannot be instantiated spring?

Abstract class, we have heard that abstract class are classes which can have abstract methods and it can't be instantiated. We cannot instantiate an abstract class in Java because it is abstract, it is not complete, hence it cannot be used.

Can we call super in abstract class?

We can treat an abstract class as a superclass and extend it; its subclasses can override some or all of its inherited abstract methods. If through this overriding a subclass contains no more abstract methods, that class is concrete (and we can construct objects directly from it).

Can we inherit abstract class in Java?

If a class is declared abstract, it cannot be instantiated. To use an abstract class, you have to inherit it from another class, provide implementations to the abstract methods in it. If you inherit an abstract class, you have to provide implementations to all the abstract methods in it.

Can an abstract class be a final class?

If you declare a class abstract, to use it, you must extend it and if you declare a class final you cannot extend it, since both contradict with each other you cannot declare a class both abstract and final if you do so a compile time error will be generated.