![]() Package program which is save with S.java and compile by javac -d. (dot) then it create a folder at current working directory. ![]() When we give specific path then it create a new folder at that location and when we use. The modifier of method of class or interface which is present in the package must be public (This rule is optional in case of interface because interface methods by default public)įor compilation of package program first we save program with public className.java and it compile using belowĮxplanations: In above syntax "-d" is a specific tool which is told to java compiler create a separate folder for the given package in given path.(This is not applicable in the case of the interface because interface has no constructor.) Modifier of the constructor of the class which is present in the package must be public.Package program should not contain any main class (that means it should not contain any main()).Any package program can contain only one public class or only one public interface but it can contain any number of normal classes.Choose an appropriate class name or interface name and whose modifier must be public.Package statement should be the first statement of any package program.User defined package are those which are developed by java programmer and supply as a part of their project to deal with common requirement. If any package is design by the user is known as user defined package. If you go the frontpage of my tutorial website, you can see a list of what I have covered so far. I have covered many of these packages (APIs) in separate tutorials. The Java platform comes with a lot of built-in Java packages.These packages contain classes for all kinds of purposes that programmers often need, like reading and writing files from the local hard disk, sending and receiving data over networks and the internet, connecting to databases, and many, many other things. Package are classified into two type which are given below. Redundancy (repetition) of code is minimized Enumerations and annotation types are special kinds of classes and interfaces, respectively,Īdvantage of package Package is used to categorize the classes and interfaces so that they can be easily maintainedĪpplication development time is less, because reuse the codeĪpplication memory space is less (main memory)Īpplication performance is enhance (improve) Note that types refers to classes, interfaces, enumerations, and annotation types. To make types easier to find and use, to avoid naming conflicts, and to control access, programmers bundle groups of related types into packages.Ī package is a grouping of related types providing access protection and name space management. Otherwise, the compiler will throw an error.ġ3) The class cannot implement two interfaces in java that have methods with same name but different return type.Īn interface can inherit one or more interfaces using extends keyword, but no interface can implements any other interfaces. It has to extend another interface if needed.ġ1) An interface which is declared inside another interface is referred as nested interface.ġ2) At the time of declaration, interface variable must be initialized. Class can extend only one class but implement any number of interfaces.ġ0) An interface cannot implement another Interface. It is necessary that the class must implement all the methods declared in the interfaces.ģ) Class should override all the abstract methods declared in the interface.Ĥ) The interface allows sending a message to an object without concerning which classes it belongs.ĥ) Class needs to provide functionality for the methods declared in the interface.Ħ) All methods in an interface are implicitly public and abstract.Ĩ) An interface reference can point to objects of its implementing classes.ĩ) An interface can extend from one or many interfaces. While in Interface only one specifier is used- Public.Ģ) A Java class can implement multiple Java Interfaces. The access specifiers used with classes are private, protected and public.The interface cannot contain concrete(with implementation) methods. ![]() In class, you can instantiate variable and create an object.Let's discover some more facts about "Interface and Class."ġ) Difference between Class and Interface. In this example, show table interface has only one method, its implementation is provided in the class. ![]() When you create an interface it defines what a class can do without saying anything about how the class will do it. The Interface is a pure abstract class.They are syntactically similar to classes, but you cannot create an instance of an Interface and their methods are declared without anybody.The Interface is used to achieve complete abstraction in Java. Interface, package and Access Modifiers Java Interface
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