- Can we override static method?
- Can abstract class have constructor?
- Can abstract methods have return type?
- Is it necessary for abstract class to have abstract method?
- What will happen if we do not override all the abstract methods in Sub class?
- What happens if an abstract method is not defined?
- How do you declare an abstract method?
- What is difference between abstract class and interface?
- Can we override non abstract method in Java?
Can we override static method?
Can we Override static methods in java.
We can declare static methods with same signature in subclass, but it is not considered overriding as there won’t be any run-time polymorphism..
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.
Can abstract methods have return type?
Must all abstract methods in java be declared with void return type? No, They can declared to return any object type, primitive type and, also declared to return void to indicate it return nothing. … An abstract method can’t have method body.
Is it necessary for abstract class to have abstract method?
It’s not necessary for an abstract class to have abstract method. We can mark a class as abstract even if it doesn’t declare any abstract methods. If abstract class doesn’t have any method implementation, its better to use interface because java doesn’t support multiple class inheritance.
What will happen if we do not override all the abstract methods in Sub class?
Extending an abstract class If you don’t, a compile time error will be generated for each abstract method (that you don’t override) saying “subclass_name is not abstract and does not override abstract method abstractmethod_name in classname”.
What happens if an abstract method is not defined?
An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed. … However, if it does not, then the subclass must also be declared abstract .
How do you declare an abstract method?
To declare an abstract method, use this general form: abstract type method-name(parameter-list); As you can see, no method body is present. Any concrete class(i.e. class without abstract keyword) that extends an abstract class must override all the abstract methods of the class.
What is difference between abstract class and interface?
Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior. … A Java class can implement multiple interfaces but it can extend only one abstract class.
Can we override non abstract method in Java?
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.