Package And Interface In Java Pdf

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Another unique feature in Java is Packages. Packages are containers for classes that are used to keep the class name space compartmentalized.

Java Interface

It organizes classes into single unit. In Java already many predefined packages are available, used while programming. For example: java. Advantages of Packages Packages provide code reusability, because a package has group of classes. It helps in resolving naming collision when multiple packages have classes with the same name. Package also provides the hiding of class facility. Thus other programs cannot use the classes from hidden package.

In this tutorial, we will learn about Java interfaces. We will learn how to implement interfaces and when to use them in detail with the help of examples. An interface is a fully abstract class. It includes a group of abstract methods methods without a body. To use an interface, other classes must implement it. We use the implements keyword to implement an interface. In the above example, we have created an interface named Polygon.

The -d switch specifies the destination where to put the generated class file. If you want to keep the package within the same directory, you can use. How to run java package program You need to use fully qualified name e. Simple etc to run the class. To Compile: javac -d.

Difference Between Packages and Interfaces in Java

Packages and Interfaces both acts as a container. The content in packages and interfaces can be used by the classes by importing and implementing it correspondingly. The basic difference between packages and interfaces is that a package contains a group of classes and interfaces whereas, an interface contains methods and fields. Interfaces is a group of abstract methods and constant fields. Keyword Packages are created using "Package" keyword. Interface are created using "Interface" keyword. Access keyword Packages can be imported using "import" keyword.

The main difference between package and interface is that a package is a collection of related classes and interfaces while an interface is a collection of fields and abstract methods. Package and interface are two main concepts in Object Oriented Programming based languages such as Java. A package has a set of associated classes and interfaces. An interface has a set of fields and abstract methods. A package is a group or a collection that consist of related classes and interfaces. There are two types of packages in a programming language.

Like a class, an interface can have methods and variables, but the methods declared in an interface are by default abstract only method signature, no body. 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. A class that implements an interface must implement all the methods declared in the interface.


For example, in Java, all the classes and interfaces which perform input and output operations are stored in uicheritagegarden.org package. ➢ Packages hide the classes and.


Difference Between Packages and Interfaces in Java

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.

Chapter Figure Synopsis Class Name: java.

Packages in Java: How to Create/Import Package

It helps organize your classes into a folder structure and make it easy to locate and use them. More importantly, it helps improve code reusability. Each package in Java has its unique name and organizes its classes and interfaces into a separate namespace, or name group. Although interfaces and classes with the same name cannot appear in the same package, they can appear in different packages. This is possible by assigning a separate namespace to each Java package. Syntax:- package nameOfPackage; The following video takes you through the steps of creating a package. Click here if the video is not accessible.

Package in Java is a mechanism to encapsulate a group of classes, sub packages and interfaces. Packages are used for:. All we need to do is put related classes into packages. After that, we can simply write an import class from existing packages and use it in our program.


A Package can be defined as a grouping of related types classes, interfaces, interfaces. Below given package example contains interface named animals.


Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available. To create a package, you choose a name for the package naming conventions are discussed in the next section and put a package statement with that name at the top of every source file that contains the types classes, interfaces, enumerations, and annotation types that you want to include in the package. The package statement for example, package graphics; must be the first line in the source file.

It helps organize your classes into a folder structure and make it easy to locate and use them. More importantly, it helps improve code reusability. Each package in Java has its unique name and organizes its classes and interfaces into a separate namespace, or name group. Although interfaces and classes with the same name cannot appear in the same package, they can appear in different packages. This is possible by assigning a separate namespace to each Java package.

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Interface in Java

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