- Why we Cannot override static method?
- Can we override final method?
- What is purpose of abstract class?
- Can abstract class have default method?
- Can we override static method?
- Which is better abstract class or interface?
- What are default methods?
- Can default method be overridden?
- Can we override default method of interface?
- Can we have 2 default method in interface?
- Can we inherit abstract class?
- Can we override main method?
- What is diamond problem in Java?
- Can abstract class have constructor?
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 final method?
The final method can’t be overridden. A final method declared in the Parent class cannot be overridden by a child class. If we try to override the final method, the compiler will throw an exception at compile time.
What is purpose of abstract class?
The Purpose of Abstract Classes. The purpose of abstract classes is to function as base classes which can be extended by subclasses to create a full implementation. For instance, imagine that a certain process requires 3 steps: The step before the action.
Can abstract class have default method?
Abstract class can have abstract and non-abstract methods. From Java 8, it can have default and static methods also. Final Variables: Variables declared in a Java interface are by default final. An abstract class may contain non-final variables.
Can we override static method?
Can we override a static method? No, we cannot override static methods because method overriding is based on dynamic binding at runtime and the static methods are bonded using static binding at compile time. So, we cannot override static methods.
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.
What are default methods?
Default methods enable you to add new functionality to existing interfaces and ensure binary compatibility with code written for older versions of those interfaces. In particular, default methods enable you to add methods that accept lambda expressions as parameters to existing interfaces.
Can default method be overridden?
If any class in the hierarchy has a method with same signature, then default methods become irrelevant. A default method cannot override a method from java. … So even if we have Object class methods defined as default methods in interfaces, it will be useless because Object class method will always be used.
Can we override default method of interface?
If you have default method in an interface, it is not mandatory to override (provide body) it in the classes that are already implementing this interface. In short, you can access the default methods of an interface using the objects of the implementing classes.
Can we have 2 default method in interface?
Multiple Defaults With default functions in interfaces, there is a possibility that a class is implementing two interfaces with same default methods. The following code explains how this ambiguity can be resolved. First solution is to create an own method that overrides the default implementation.
Can we inherit abstract class?
An abstract class defines the identity of a class. An interface can inherit multiple interfaces but cannot inherit a class. An abstract class can inherit a class and multiple interfaces. … An abstract class can declare constructors and destructors.
Can we override main method?
No, we cannot override main method of java because a static method cannot be overridden. The static method in java is associated with class whereas the non-static method is associated with an object. … Therefore, it is not possible to override the main method in java.
What is diamond problem in Java?
Then, if you call the demo() method using the object of the subclass compiler faces an ambiguous situation not knowing which method to call. This issue is known as diamond problem in Java. Due to this Java does not support multiple inheritance i.e., you cannot extend more than one other class.
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.