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Can a non abstract class have abstract method?
A class that is declared using “abstract” keyword is known as abstract class. 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.
Can abstract class have methods in Java?
An abstract class can have a data member, abstract method, method body (non-abstract method), constructor, and even main() method.
Can an abstract method have a body?
Abstract methods cannot have body. Abstract class can have static fields and static method, like other classes. An abstract class cannot be declared as final. If a class extends an abstract class, then it should define all the abstract methods (override) of the base abstract class.
How are abstract classes and methods used in Java?
Let’s take an example of the Abstract class and try to understand how they can be used in Java. In this example, we created an abstract class A that contains a method callme () and Using class B, we are extending the abstract class. calling… Abstract classes can also have non abstract methods along with abstract methods.
Can a class be declared without an abstract method?
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.
How are abstract classes different from normal classes?
Abstract classes are not Interfaces. They are different, we will study this when we will study Interfaces. An abstract class may or may not have an abstract method. But if any class has even a single abstract method, then it must be declared abstract. Abstract classes can have Constructors, Member variables and Normal methods.
Do you need an abstract keyword in Java?
An abstract class must be declared with an abstract keyword. It can have abstract and non-abstract methods. It cannot be instantiated. It can have constructors and static methods also.