What will be the output of the following Java program interface calculate?

What will be the output of the following Java code interface calculate?

What will be the output of the following Java program? Explanation: class displayA implements the interface calculate by doubling the value of item, where as class displayB implements the interface by dividing item by item, therefore variable x of class displayA stores 4 and variable x of class displayB stores 1.

Which of these keywords is used to define method in Java?

interface: Java interface keyword is used to declare an interface. It can have only abstract methods. long: Java long keyword is used to declare a variable that can hold a 64-bit integer. native: Java native keyword is used to specify that a method is implemented in native code using JNI (Java Native Interface).

Which is correct about Java interface?

An interface in Java is a blueprint of a class. It has static constants and abstract methods. The interface in Java is a mechanism to achieve abstraction. There can be only abstract methods in the Java interface, not method body.

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Which of these keywords is used to define interfaces in Java?

To declare an interface, use interface keyword. It is used to provide total abstraction. That means all the methods in an interface are declared with an empty body and are public and all fields are public, static and final by default.

What is the use of final keyword in Java?

Java final keyword is a non-access specifier that is used to restrict a class, variable, and method. If we initialize a variable with the final keyword, then we cannot modify its value. If we declare a method as final, then it cannot be overridden by any subclasses.

What is interface used for?

You use an interface to define a protocol of behavior that can be implemented by any class anywhere in the class hierarchy. Interfaces are useful for the following: Capturing similarities among unrelated classes without artificially forcing a class relationship.

What are the important keywords in Java?

Java Keyword List

Keyword Description
import Used to include or reference other packages/classes into the program.
instanceof Used to check if the given object is an instance of another class.
int Data type to hold a 32-bit integer value.
interface Used for declaring an interface.

What is the use of this keyword?

The this keyword refers to the current object in a method or constructor. The most common use of the this keyword is to eliminate the confusion between class attributes and parameters with the same name (because a class attribute is shadowed by a method or constructor parameter).

What are default methods?

The default methods were introduced to provide backward compatibility so that existing interfaces can use the lambda expressions without implementing the methods in the implementation class. Default methods are also known as defender methods or virtual extension methods.

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Which of the following is correct about interface?

Which of the following statements is correct about an interface?

1) An interface can be implemented by multiple classes in the same program.
3) The functions declared in an interface have a body
4) A class that implements an interface can explicitly implement members of that interface.

Is overriding possible in Java?

In Java, methods are virtual by default. We can have multilevel method-overriding. Overriding vs Overloading : … Overriding is about same method, same signature but different classes connected through inheritance.

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