Can we create object of abstract class?

You can't create an object of an abstract class type. However, you can use pointers and references to abstract class types. You create an abstract class by declaring at least one pure virtual member function. That's a virtual function declared by using the pure specifier ( = 0 ) syntax.

Why can't we create the object of an abstract class?

Because an abstract class is an incomplete class (incomplete in the sense it contains abstract methods without body and output) we cannot create an instance or object; the same way you say for an interface.

Can we create class of abstract class?

You cannot create objects of abstract class because abstract class cannot be instantiated.

Can we create object for abstract and interface?

You cannot create an object of abstract class or interface since they are incomplete class (interface is not even considered as a class.)

How many objects of abstract class can we create?

Abstract Class is Half Define Class. Abstract class not allowed to create an Instance (Object). So, we can not create any instance then answer is 0. There are no objects for abstract class.

Can we create object for abstract class in Java

Can we create constructor of abstract class?

Yes! Abstract classes can have constructors! Yes, when we define a class to be an Abstract Class it cannot be instantiated but that does not mean an Abstract class cannot have a constructor. Each abstract class must have a concrete subclass which will implement the abstract methods of that abstract class.

Can we create object of interface?

Like abstract classes, interfaces cannot be used to create objects (in the example above, it is not possible to create an "Animal" object in the MyMainClass) Interface methods do not have a body - the body is provided by the "implement" class. On implementation of an interface, you must override all of its methods.

Can we create object of static class?

You cannot create an object of a static class and cannot access static members using an object. C# classes, variables, methods, properties, operators, events, and constructors can be defined as static using the static modifier keyword.

Can we inherit abstract class?

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

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 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 we create an object of final class?

Note that by making final class, you are just stopping the class to be inherited. Otherwise, final class is as normal class in java. Means, we can create objects of the class and call methods in java program etc.

Can we overload abstract method in Java?

Yes, you can have overloaded methods (methods with the same name different parameters) in an interface.

Why interface objects are not created?

We can't create object of interfaces because of the reason that : Interface is basically a complete abstract class. That means Interface only have deceleration of method not their implementation.

Can abstract class have static methods in Java?

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.

Can an abstract class be extended?

An abstract class can extend another abstract class. And any concrete subclasses must ensure that all abstract methods are implemented. Abstract classes can themselves have concrete implementations of methods. These methods are inherited just like a method in a non-abstract class.

Can abstract class have main () function defined inside it?

Can abstract class have main() function defined inside it? Explanation: This is a property of abstract class. It can define main() function inside it. There is no restriction on its definition and implementation.

Can we inherit private class?

Members of a class that are declared private are not inherited by subclasses of that class. Only members of a class that are declared protected or public are inherited by subclasses declared in a package other than the one in which the class is declared. The answer is No. They do not.

Can a class extend multiple abstract classes?

A class can extend at most one abstract class, but may implement many interfaces. That is, Java supports a limited form of multiple inheritance.

Can we create immutable class in Java?

Immutable class in java means that once an object is created, we cannot change its content. In Java, all the wrapper classes (like Integer, Boolean, Byte, Short) and String class is immutable. We can create our own immutable class as well.

Can we create constructor of interface?

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. From Java9 onwards interfaces allow private and private static methods.

Can we create instance of sealed class?

you can create instance of sealed class but not in static class. You need the class name to access the members and methods of static class whereas in case of sealed class you can create the instance of it.

Can we create object of constructor?

Simply speaking, a constructor does not create an object. It just initializes the state of the object. It's the new operator which creates the object.

Can we write only concrete methods in abstract class?

If you want to use the concrete method in an abstract class you need to inherit the class, provide implementation to the abstract methods (if any) and then, you using the subclass object you can invoke the required methods.

Can anonymous class have constructor?

Since they have no name, we can't extend them. For the same reason, anonymous classes cannot have explicitly declared constructors.