- Does abstract method have body?
- Can an abstract class have a constructor?
- Can we declare abstract class as static?
- Can you call an abstract method?
- Can an interface have a constructor?
- Can we instantiate a class which does not have even single abstract methods but declared as abstract?
- Can we declare abstract class as final?
- Why does an abstract class have a constructor?
- Can you instantiate an abstract class and what is an inner class?
- Why can’t you instantiate an abstract class?
- Can I instantiate an abstract class?
- Can an abstract class have a constructor C++?
- Can’t have an abstract method in a non abstract class?
- Can we declare abstract method without abstract class?
- Can’t instantiate abstract class with abstract methods?
Does abstract method have body?
Abstract methods means there is no default implementation for it and an implementing class will provide the details.
So, it’s exactly as the error states: your abstract method can not have a body.
The reason you would do something like this is if multiple objects can share some behavior, but not all behavior..
Can an abstract class have a constructor?
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 declare abstract class as static?
Declaring abstract method static 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 you call an abstract method?
An abstract method is a method without a body. So you can’t just call an abstract method of an abstract class (you cannot instantiate an abstract class directly). … Alternatively you can remove the abstract keyword from the methods in your game class but still @Override them in your subclass.
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.
Can we instantiate a class which does not have even single abstract methods but declared as abstract?
Yes we can have an abstract class without Abstract Methods as both are independent concepts. Declaring a class abstract means that it can not be instantiated on its own and can only be sub classed. Declaring a method abstract means that Method will be defined in the subclass.
Can we declare abstract class as final?
In short, an abstract class cannot be final in Java, using both abstract and final modifier with a class is illegal in Java. … An abstract method must be overridden to be useful and called but when you make the abstract method final it cannot be overridden in Java, hence there would be no way to use that method.
Why does an abstract class have a constructor?
The main purpose of the constructor is to initialize the newly created object. In abstract class, we have an instance variable, abstract methods, and non-abstract methods. … The constructor inside the abstract class can only be called during constructor chaining i.e. when we create an instance of sub-classes.
Can you instantiate an abstract class and what is an inner class?
Infact annonymous inner type allows you to create a no-name subclass of the abstract class and an instance of this. Abstract classes cannot be instantiated – this is by definition and design.
Why can’t you instantiate 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. You CAN instantiate an abstract class. You only need to provide a concrete subclass.
Can I instantiate an abstract class?
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 abstract class have a constructor C++?
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’t have an abstract method in a non abstract class?
You cannot declare abstract methods in a non-abstract class, final dot. That would simply defile the concept of abstract methods. What you can do is have your class hierarchy implement interfaces dictating the required methods to implement.
Can we declare abstract method without abstract class?
If it contains at least one abstract method, it must be declared abstract. … And yes, you can declare abstract class without defining an abstract method in it. Once you declare a class abstract it indicates that the class is incomplete and, you cannot instantiate it.
Can’t instantiate abstract class with abstract methods?
A class that is derived from an abstract class cannot be instantiated unless all of its abstract methods are overridden. You may think that abstract methods can’t be implemented in the abstract base class. … Even if they are implemented, designers of subclasses will be forced to override the implementation.