- Can we inherit child class from 2 base classes?
- Can we override abstract method?
- What is difference between interface and abstract class?
- Can abstract method have body?
- Can we override static method?
- Can abstract class be overridden?
- Can abstract class have constructor?
- Why can’t we instantiate an abstract class?
- Can interface inherit abstract class?
- Is class an abstract?
- Can a single class inherit from multiple abstract classes?
- Can an abstract class inherit another abstract class in Java?
- Can abstract class have private methods?
- Can abstract class have normal methods?
- Which is better abstract class or interface?
Can we inherit child class from 2 base classes?
Multiple Inheritance is a feature of C++ where a class can inherit from more than one classes.
The constructors of inherited classes are called in the same order in which they are inherited..
Can we override abstract method?
We use the abstract keyword to create abstract classes and methods. An abstract method doesn’t have any implementation (method body). … 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.
What is difference between interface and abstract class?
Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. … Variables declared in a Java interface is by default final. An abstract class may contain non-final variables. Members of a Java interface are public by default.
Can abstract method have body?
Abstract methods are declaration only and it will not have implementation. It will not have a method body. A Java class containing an abstract class must be declared as abstract class. An abstract method can only set a visibility modifier, one of public or protected.
Can we override static method?
Can we Override static methods in java? We can declare static methods with the same signature in the subclass, but it is not considered overriding as there won’t be any run-time polymorphism. Hence the answer is ‘No’.
Can abstract class be overridden?
An abstract method has no implementation. … Subclasses of an abstract class must implement (override) all abstract methods of its abstract superclass. The non-abstract methods of the superclass are just inherited as they are. They can also be overridden, if needed.
Can abstract class have 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.
Why can’t we 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 interface inherit abstract class?
An interface can inherit multiple interfaces but cannot inherit a class. An abstract class can inherit a class and multiple interfaces. … An interface can have only public abstract methods. An abstract class has protected and public abstract methods.
Is class an abstract?
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.
Can a single class inherit from multiple abstract classes?
Basically, the rule says that you can inherit from (extend) as many classes as you want, but if you do, only one of those classes can contain concrete (implemented) methods. … 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 an abstract class inherit another abstract class in Java?
Abstract Class 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 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 abstract class have normal methods?
It can have abstract methods(methods without body) as well as concrete methods (regular methods with body). A normal class(non-abstract class) cannot have abstract methods. … An abstract class can not be instantiated, which means you are not allowed to create an object of it.
Which is better abstract class or interface?
The short answer: An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.