WHAT IS interface in Java with real time example?

An interface in java it has static constants and abstract methods only. for real time example – it is 100\% abstraction. example is, Comparator Interface. If a class implements this interface, then it can be used to sort a collection.

What types of methods can exist in an interface in Java?

In the Java programming language, an interface is a reference type, similar to a class, that can contain only constants, method signatures, default methods, static methods, and nested types. Method bodies exist only for default methods and static methods.

What is allowed in a Java interface?

An interface can have constants, these constants are public, static and final(Implicitly). A class implementing an interface can also be an abstract class. An abstract class which is implementing an interface need not implement all abstract method. A class can Implement more than one Interface.

In which scenario we can use abstract class and interface?

If you want to implement or force some methods across classes must be for uniformity you can use an interface. So to increase reusability via inheritance use the abstract class as it is nothing but a base class and to force methods to use interfaces.

What type of variable can be defined in an interface?

What type of variable can be defined in an interface? Explanation: variable defined in an interface is implicitly final and static. They are usually written in capital letters.

What is an interface in Java What is the real use of an interface?

An Interface in Java programming language is defined as an abstract type used to specify the behavior of a class. A Java interface contains static constants and abstract methods. A class can implement multiple interfaces. In Java, interfaces are declared using the interface keyword.

What type of methods an interface contain by default?

What type of methods an interface contain by default? Explanation: By default, interface contains abstract methods. The abstract methods need to be implemented by concrete classes.

CAN interface have variables in Java?

An interface can have methods and variables just like the class but the methods declared in interface are by default abstract (only method signature, no body, see: Java abstract method). Also, the variables declared in an interface are public, static & final by default.

What are the main objectives of having interface in the Java programming?

Purpose of the interface Provides communication − One of the uses of the interface is to provide communication. Through interface you can specify how you want the methods and fields of a particular type.

In what scenarios should you make a Method class abstract?

A method without body (no implementation) is known as abstract method. A method must always be declared in an abstract class, or in other words you can say that if a class has an abstract method, it should be declared abstract as well.

When should we use interface in Java?

Why do we use interface?

1. It is used to achieve total abstraction.
2. Since java does not support multiple inheritance in case of class, but by using interface it can achieve multiple inheritance .
3. It is also used to achieve loose coupling.
4. Interfaces are used to implement abstraction.