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..
In respect to this, can packages have interfaces?
Interfaces must have either public or package protection, just like classes. Interfaces, like classes, can belong to a package by adding a package statement to the first line of the class file. Interfaces can also import other interfaces and classes from other packages, just as classes can.
Also, what is the difference between package and class in Java? In Java, packages are used to organize classes belonging to the same functionality and Java packages can be stored in compressed file called JAR files. Class is an entity that determines how an object will behave and what the object will contain. Package is a collection of classes and class is a collection of objects.
Then, wHAT IS interface and package in Java?
There is no concept of multiple-inheritance in Java, but, Interfaces in Java are, for the most part, unique to the language, play a role similar to that of multiple-inheritance. Another unique feature in Java is Packages. Packages are containers for classes that are used to keep the class name space compartmentalized.
How do you define a package in Java?
Creating a package in Java is a very easy task. Choose a name for the package and include a package command as the first statement in the Java source file. The java source file can contain the classes, interfaces, enumerations, and annotation types that you want to include in the package.
Related Question Answers
How do we add class or interface to a package?
To add a class or interface to a package: - Add package myPackageName ; as the first Java statement of the source file.
- In your development directory, store the source file in a directory structure corresponding to your package name.
Can a constructor be private?
Yes. Class can have private constructor. Even abstract class can have private constructor. By making constructor private, we prevent the class from being instantiated as well as subclassing of that class.Can I import same package class twice?
Yes, we can import same package/class multiple times. It will not create any problem . Neither compiler nor JVM complains wil complain about it. JVM will internally load the class only once no matter how many times you import the same class.Can package have interfaces in Java?
Package in Java is a mechanism to encapsulate a group of classes, sub packages and interfaces. Packages are used for: For example there can be two classes with name Employee in two packages, college.What is sub package in Java?
Subpackage in Java Package inside the package is called the subpackage. It should be created to categorize the package further. and put the Input/Output related classes in io package, Server and ServerSocket classes in net packages and so on.What is the default package in Java?
The default package is an unnamed package. The unnamed package contains java classes whose source files did not contain a package declaration. The purpose of default package is for convenience when developing small or temporary applications or when just beginning development.How do I import a package?
import keyword is used to import built-in and user-defined packages into your java source file so that your class can refer to a class that is in another package by directly using its name.Which package contains classes and interfaces for networking?
package java.net
What is Interface explain with example?
An interface is just like Java Class, but it only has static constants and abstract method. Java uses Interface to implement multiple inheritance. A Java class can implement multiple Java Interfaces. All methods in an interface are implicitly public and abstract.When would you use an interface?
Use abstract class when you want to extend a comman base and where you want to provide a default implementation to the abstract method. Use interface when you want to exactly implement all the abstract methods to the class implementaing the interface and no default body to a method can be provided.Can an interface implement a class?
A class can implement more than one interface. An interface can extends another interface or interfaces (more than one interface) . A class that implements interface must implements all the methods in interface. All the methods are public and abstract.Can abstract class have constructor?
Yes, an abstract class can have a constructor in Java. You can either explicitly provide a constructor to abstract class or if you don't, the compiler will add default constructor of no argument in abstract class. This is true for all classes and it also applies to an abstract class.Can an abstract class implement an interface?
In Java, an abstract class can implement an interface, and not provide implementations of all of the interface's methods. It is the responsibility of the first concrete class that has that abstract class as an ancestor to implement all of the methods in the interface.How do you implement an interface?
Implementing an Interface. To declare a class that implements an interface, you include an implements clause in the class declaration. Your class can implement more than one interface, so the implements keyword is followed by a comma-separated list of the interfaces implemented by the class.Can we extend two classes in Java?
Java does not support multiple inheritance, that's why you can't extend a class from two different classes at the same time. Rather, use a single class to extend from, and use interfaces to include additional functionality.Why is interface used in Java?
The interface in Java is a mechanism to achieve abstraction. There can be only abstract methods in the Java interface, not method body. It is used to achieve abstraction and multiple inheritance in Java. In other words, you can say that interfaces can have abstract methods and variables.Why packages are used in Java?
Packages are used in Java in order to prevent naming conflicts, to control access, to make searching/locating and usage of classes, interfaces, enumerations and annotations easier, etc.What is API in Java?
Java application programming interface (API) is a list of all classes that are part of the Java development kit (JDK). It includes all Java packages, classes, and interfaces, along with their methods, fields, and constructors. These prewritten classes provide a tremendous amount of functionality to a programmer.What is javar?
Javar (, also Romanized as Jūr) is a village in Baraan-e Shomali Rural District, in the Central District of Isfahan County, Isfahan Province, Iran. At the 2006 census, its population was 542, in 148 families. 
