1/21/2024 0 Comments Java interface design tutorial![]() JavaFX was moved out from the JDK in JDK 11, but still available as a separate module. The latest JavaFX, which was integrated into JDK 8, was meant to replace Swing.JFC has been integrated into core Java since JDK 1.2. JFC consists of Swing, Java2D, Accessibility, Internationalization, and Pluggable Look-and-Feel Support APIs. Swing API, a much more comprehensive set of graphics libraries that enhances the AWT, was introduced as part of Java Foundation Classes (JFC) after the release of JDK 1.1.Most of the AWT UI components have become obsolete and should be replaced by newer Swing UI components. There are current three sets of Java APIs for graphics programming: AWT ( Abstract Windowing Toolkit), Swing and JavaFX. I will describe another important OO concept called nested class (or inner class) in this article. ![]() I shall assume that you have a good grasp of OOP, including composition, inheritance, polymorphism, abstract class and interface otherwise, read the earlier articles. However, re-using them are not so difficult, if you follow the API documentation, samples and templates provided. Writing your own graphics classes (and re-inventing the wheels) is mission impossible! These graphics classes, developed by expert programmers, are highly complex and involve many advanced design patterns. In this article, I shall show you how you can reuse the graphics classes provided in JDK for constructing your own Graphical User Interface (GUI) applications. These classes are self-contained and are reusable. You can create high-level abstract data types called classes to mimic real-life things. As discussed, OOP permits higher level of abstraction than traditional Procedural-Oriented Languages (such as C). For example, the MouseListener interface in the package extended, which is defined as − ExampleĪn interface with no methods in it is referred to as a tagging interface.So far, we have covered the basic programming constructs (such as variables, data types, decision, loop, array and method) and introduced the important concept of Object-Oriented Programming (OOP). The most common use of extending interfaces occurs when the parent interface does not contain any methods. ![]() HockeyDemo hockeyDemo = new HockeyDemo() Public class MammalInt implements Animal The implements keyword appears in the class declaration following the extends portion of the declaration. If a class does not perform all the behaviors of the interface, the class must declare itself as abstract.Ī class uses the implements keyword to implement an interface. When a class implements an interface, you can think of the class as signing a contract, agreeing to perform the specific behaviors of the interface. ![]() Methods in an interface are implicitly public. You do not need to use the abstract keyword while declaring an interface.Įach method in an interface is also implicitly abstract, so the abstract keyword is not needed. Interfaces have the following properties −Īn interface is implicitly abstract. Any number of abstract method declarations\ Here is a simple example to declare an interface − Exampleįollowing is an example of an interface − The interface keyword is used to declare an interface. The only fields that can appear in an interface must be declared both static and final.Īn interface is not extended by a class it is implemented by a class.Īn interface can extend multiple interfaces. However, an interface is different from a class in several ways, including −Īn interface does not contain any constructors.Īll of the methods in an interface are abstract.Īn interface cannot contain instance fields. ![]() Interfaces appear in packages, and their corresponding bytecode file must be in a directory structure that matches the package name. The byte code of an interface appears in a. java extension, with the name of the interface matching the name of the file. Unless the class that implements the interface is abstract, all the methods of the interface need to be defined in the class.Īn interface is similar to a class in the following ways −Īn interface can contain any number of methods.Īn interface is written in a file with a. And an interface contains behaviors that a class implements. But a class describes the attributes and behaviors of an object. Writing an interface is similar to writing a class. Method bodies exist only for default methods and static methods. A class implements an interface, thereby inheriting the abstract methods of the interface.Īlong with abstract methods, an interface may also contain constants, default methods, static methods, and nested types. An interface is a reference type in Java. ![]()
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