- Can abstract class have constructor?
- Can abstract class have static methods?
- Can we have main method in interface?
- What is the main difference between abstract method and final method in Java?
- Can we write main method in abstract class?
- Can an interface be final?
- Can we override the final method?
- Can we declare abstract method as private?
- Can an interface be static?
- Can we declare final inside abstract class and interface both?
- Can an abstract class have a final method?
- Can we have a method which is both abstract and final?
- Which methods Cannot be overridden?
- Why we Cannot override static method?
- Can we override static method?
- Can we declare constructor inside an interface?
- Why static methods are not allowed in interface?
- Can we override the abstract method?
Can abstract class have constructor?
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 class have static methods?
Can an abstract class have static methods? Yes, abstract class can have Static Methods. The reason for this is Static methods do not work on the instance of the class, they are directly associated with the class itself.
Can we have main method in interface?
Answer : Yes, we can provide different implementation of main() declared in an interface and classes implementing that interface by overriding method and can overload static main method if defined in an interface. Some more information regarding interface changes in Java 8.
What is the main difference between abstract method and final method in Java?
Difference between abstract method and final method in Java. The abstract method is incomplete while the final method is regarded as complete. The only way to use an abstract method is by overriding it, but you cannot override a final method in Java.
Can we write main method in abstract class?
Yes, you can use the main method in abstract class. The main method is a static method so it is associated with Class, not with object/ instance. … In main method, you can not create an instance of the abstract class but you can instantiate other concrete class.
Can an interface be final?
If you make an interface final, you cannot implement its methods which defies the very purpose of the interfaces. Therefore, you cannot make an interface final in Java. Still if you try to do so, a compile time exception is generated saying “illegal combination of modifiers − interface and final”.
Can we override the final method?
You use the final keyword in a method declaration to indicate that the method cannot be overridden by subclasses.
Can we declare abstract method as private?
Declaring an abstract method private 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 an interface be static?
Similar to Default Method in Interface, the static method in an interface can be defined in the interface, but cannot be overridden in Implementation Classes. To use a static method, Interface name should be instantiated with it, as it is a part of the Interface only.
Can we declare final inside abstract class and interface both?
An interface is a pure abstract class. Hence, all methods in an interface are abtract , and must be implemented in the child classes. So, by extension, none of them can be declared as final .
Can an abstract class have a final method?
therefore, a final abstract combination is illegal for classes. Hence, a final class cannot contain abstract methods whereas an abstract class can contain a final method.
Can we have a method which is both abstract and final?
A method can never, ever, ever be marked as both abstract and final, or both abstract and private. Think about it—abstract methods must be implemented (which essentially means overridden by a subclass) whereas final and private methods cannot ever be overridden by a subclass.
Which methods Cannot be overridden?
A method declared final cannot be overridden. A method declared static cannot be overridden but can be re-declared. If a method cannot be inherited, then it cannot be overridden. A subclass within the same package as the instance’s superclass can override any superclass method that is not declared private or final.
Why we Cannot override static method?
Static methods cannot be overridden because they are not dispatched on the object instance at runtime. The compiler decides which method gets called. Static methods can be overloaded (meaning that you can have the same method name for several methods as long as they have different parameter types).
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 we declare constructor inside an 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.
Why static methods are not allowed in interface?
Java interface static method is part of interface, we can’t use it for implementation class objects. … This is because it’s not allowed in java, since Object is the base class for all the classes and we can’t have one class level static method and another instance method with same signature.
Can we override the 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.