Chapter 9: Inheritance and Interfaces
Inheritance Hierarchies. ? Implementing Subclasses. ? Overriding Methods. ? Polymorphism. ? Object: The Cosmic Superclass. ? Interface Types
Unit 2 Inheritance Packages and Interfaces Dr. Suresh Yadlapati
https://www.pvpsiddhartha.ac.in/dep_it/lecture%20notes/JAVA19/Unit%202.pdf
INHERITANCE AND INTERFACES UNIT -2
INHERITANCE AND INTERFACES. 2.1 InherItance. Inheritance is the mechanism in java by which one class is allow to inherit the features.
CS200: Advanced OO in Java interfaces inheritance
https://www.cs.colostate.edu/~cs200/Spring16/slides/08-advOO.pdf
Efficient Implementation of Java Interfaces: Invokeinterface
thod table dispatch does not handle multiple inheritance and interfaces. This complication has led to a widespread misimpression that interface method
UNIT -IV INHERITANCE PACKAGES AND INTERFACES
package. 4.3Defining interface inheritance on interfaces
Java - Inheritance/Polymorphism/Interface Reusing Classes in Java
Java - Inheritance/Polymorphism/Interface. CS 4354. Fall 2012. Jill Seaman. 1. Reusing Classes in Java. • Composition. ?A new class is composed of object
Java - Inheritance/Polymorphism/Interfaces Interface 3 definitions
Java - Inheritance/Polymorphism/Interfaces. Horstmann chapters 4.1-5 & 6.1. CS 4354. Summer II 2016. Jill Seaman. 1. Interface 3 definitions used in this
Better Object Oriented Paradigm Inheritance and Interface through
propagate the difference between using object oriented class inheritance and interfaces in C# source code using cohesion measures by metrics.
Difference Between Inheritance and Interface in Java Key Difference
29 Dec 2017 and an interface is to implement abstract classes and multiple inheritance. What is Inheritance in Java? Inheritance can achieve code re ...
ADVANCED JAVA - Princeton University
Feb 10 2021 · Inheritance overview Implementation inheritance (subclassing) ?Define a new class (subclass) from another class (base class or superclass) ?The subclass inherits from the base class: instance variables (state) instance methods (behavior) ?The subclass can override instance methods in the base class (replacing with own versions) Main benefits
Interface and Inheritance in Java: Inheritance
Java has two mechanisms for inheritance: 1 Interface using implements keyword; methods only 2 Class using extends keyword; methods and variables Composition - allows a new class to specify other existing classes that are a part of it In Java composition simply means that one object is a member variable of another
Java Inheritance Interfaces - College of Computing & Informatics
Java – Inheritance Interfaces Kurt Schmidt Intro Java Classes Inheritance Casting Containers Interfaces Exceptions Nested Classes Containers and Interfaces Instances of an class implementing an interface can be viewed as objects of that type A KeyListener object whatever else it is has methods keyTyped keyPressed and keyReleased
Inheritance and Interfaces
Java API Swingsort usesapplication-specific code Inheritance terminology: a subclass (or derivedclass) inherits from a superclass (or baseclass) subclass class is a specializationof the superclass add or change functionality reuse code and interface can use subclass objects in place of superclaobjects
Java – Generics Interface and Inheritance
A Java interface is a collection of abstract methods and constants An abstract method is a method header without a method body An abstract method can be declared using the modifier abstract but because all methods in an interface are abstract usually it is left off An interface is used to establish a set of
Searches related to inheritance and interface in java filetype:pdf
Java Interface • Method Prototypes - An interface defines a set of method prototypes - Does not provide code for implementation -- just the prototypes - Can also define final constants • Class implements interface - A class that implements an interface must implement all the methods in the interface The compiler
[PDF] Unit 2 Inheritance Packages and Interfaces Dr Suresh Yadlapati M
Inheritance Packages and Interfaces Inheritance can be defined as the process where one class acquires the properties of another class
[PDF] INHERITANCE AND INTERFACES UNIT -2
Inheritance is the mechanism in java by which one class is allow to inherit the features (fields and methods) of another class It is process of deriving a new
[PDF] Chapter 9: Inheritance and Interfaces
A Java interface type declares a set of methods and their signatures Page 56 Syntax 9 4: Interface Types ? An interface declaration and a class that
[PDF] UNIT -IV INHERITANCE PACKAGES AND INTERFACES
? Inheritance provides reusability of code ? Java class can be reused in several ways by creating new class ? Reusing the properties of existing
[PDF] Inheritance in Java - WordPresscom
Inheritance in java is a mechanism in which one object acquires all the properties and behaviors of parent object • The idea behind inheritance in java is
[PDF] Inheritance in Java
In java programming multiple and hybrid inheritance is supported through interface only We will learn about interfaces later Page 4 Note: Multiple
[PDF] interface and abstract classpdf
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 It
[PDF] Java - Inheritance/Polymorphism/Interface
Java - Inheritance/Polymorphism/Interface CS 4354 Fall 2012 Jill Seaman 1 Reusing Classes in Java • Composition ?A new class is composed of object
[PDF] Java -Inheritance
The implements keyword is used by classes by inherit from interfaces Interfaces can never be extended by the classes Example: public interface Animal {}
[PDF] Java Classes Objects Inheritance Abstract and Interfaces Recap 2
the same type A Java class uses: variables to define data fields and methods to define behaviors
What is inheritance in Java?
- In other words every class in java directly or indirectly inherits Object class. By means of inheritance a class gets all the public, protected properties and methods of the super class no matter which package the sub class is present in.
How to use multiple inheritance using interfaces in Java?
- Here is the complete java program example of multiple inheritance using interfaces. Also, it will extend one class as extending one class in java is allowed. In this java program, Bird class will extend one class (Color) and use multiple inheritance properties by implementing 2 interfaces i.e. IFlyable and IEatable
What is implementation inheritance (subclassing)?
- 4 Implementation inheritance (subclassing). ?Define a new class (subclass) from another class (base class or superclass). ?The subclass inherits from the base class: – instance variables (state) – instance methods (behavior) ?The subclass can override instance methods in the base class (replacing with own versions).
Can we implement iterators in Java?
- Two Java interfaces that allow a client to iterate over items in a collection without exposing its internal representation. This course. ?Yes: use iterators in client code. ?Yes: implement iterators (Assignment 2 only). 35 Stack stack = new Stack(); ... for (String s : stack) { ... © Copyright 2021 Robert Sedgewick and Kevin Wayne 36
CSE260, Computer Science B: Honors
Stony Brook University
http://www.cs.stonybrook.edu/~cse260Recapitulate CSE160: Java Classes, Objects,
Inheritance, Abstract Classes and Interfaces
1 (c) Paul Fodor (CS Stony Brook) & PearsonObjectives
To refresh information from CSE160 about
classes, objects, inheritance, abstract classes and interfaces 2 (c) Paul Fodor (CS Stony Brook) & PearsonOO Programming Concepts
An object represents an entity in the real world that can be distinctly identified.An object has a unique state and behaviors
the state of an object consists of a set of data fields (properties) with their current values the behavior of an object is defined by a set of methods 3Class Name: Circle
Data Fields:
radius is _______Methods:
getArea()Circle Object 1
Data Fields:
radius is 1Circle Object 2
Data Fields:
radius is 25Circle Object 3
Data Fields:
radius is 125A class template
Three objects of
the Circle class (c) Paul Fodor (CS Stony Brook) & PearsonClasses
Classes are templates that define objects of
the same type.A Java class uses:
variables to define data fields and methods to define behaviorsA class provides a special type of methods
called constructorswhich are invoked to construct objects from the class 4 (c) Paul Fodor (CS Stony Brook) & Pearson5 class Circle { /** The radius of this circle */ private double radius = 1.0; /** Construct a circle object */ public Circle() { /** Construct a circle object */ public Circle(double newRadius) { radius = newRadius; /** Return the area of this circle */ public double getArea() { return radius * radius * 3.14159;Data field
Method
Constructors
Classes
(c) Paul Fodor (CS Stony Brook) & Pearson6 public class TestCircle { public static void main(String[] args) {Circle circle1 = new Circle();
Circle circle2 = new Circle(25);
Circle circle3 = new Circle(125);
System.out.println( circle1.getArea() );
System.out.println( circle2.getArea() );
System.out.println( circle3.getArea() );
//System.out.println( circle1.radius ); //System.out.println( circle2.radius ); //System.out.println( circle3.radius );Classes
(c) Paul Fodor (CS Stony Brook) & Pearson7UML Class Diagram
Circle
radius: doubleCircle()
Circle(newRadius: double)
getArea(): double circle1: Circle radius = 1.0Class name
Data fields
Constructors and
methods circle2: Circle radius = 25 circle3: Circle radius = 125UML Class Diagram
UML notation
for objects (c) Paul Fodor (CS Stony Brook) & PearsonConstructors
Constructors must have the same name as the class itself. Constructors do not have a return typenot even void. Constructors are invoked using the newoperator when an object is created they initialize objects to reference variables:ClassNameo = new ClassName();
Example:
Circle myCircle= new Circle(5.0);
A class may be declared without constructors: a no-argdefault constructorwith an empty body is implicitly declared in the class 8 (c) Paul Fodor (CS Stony Brook) & PearsonAccessing Objects
objectRefVar.dataExample:myCircle.radius
objectRefVar.methodName(arguments)Example:myCircle.getArea()
9 (c) Paul Fodor (CS Stony Brook) & Pearson10Default values
public class Test { public static void main(String[] args) { intx; // x has no default valueString y; // y has no default value
System.out.println("x is " + x);
System.out.println("y is " + y);
}Compilation error: the variables are not initializedBUT it assigns default values to data fields!
Java assigns no default value to a local variable inside a method. (c) Paul Fodor (CS Stony Brook) & Pearson11Reference Data Fields
The data fields can also be of reference types
Example:
public class Student {String name; // name has default value null
intage; // age has default value 0 booleanisScienceMajor; // isScienceMajorhas default value false char gender; // c has default value '\u0000' If a data field of a reference type does not reference any object, the data field holds a special literal value: null. public class Test { public static void main(String[] args) {Student student= new Student();
System.out.println("name? " + student.name); // nullSystem.out.println("age? " + student.age); // 0
System.out.println("isScienceMajor? " + student.isScienceMajor); // false System.out.println("gender? " + student.gender); // (c) Paul Fodor (CS Stony Brook) & Pearson12Differences between Variables of
Primitive Data Types and Object Types
1 Primitive type int i = 1 i
Object type Circle c c reference
Created using new Circle()
c: Circle radius = 1 (c) Paul Fodor (CS Stony Brook) & Pearson13Copying Variables of Primitive Data
Types and Object Types
iPrimitive type assignment i = j
Before:
1 j 2 iAfter:
2 j 2 c1Object type assignment c1 = c2
Before:
c2 c1After:
c2 c1: Circle radius = 5 c2: Circle radius = 9 c1: Circle radius = 5 c2: Circle radius = 9 -The object previously referenced by c1 is no longer referenced it is called garbage -Garbage is automatically collected by JVM = garbage collection (c) Paul Fodor (CS Stony Brook) & Pearson static vs. non-staticStatic methods & variables are scoped to a
class one static variable for all objects to share!Non-static (object) methods & variables
are scoped to a single object each object owns its non-static methods & variables 14 (c) Paul Fodor (CS Stony Brook) & Pearson15Static Variables,
Constants and Methods
Circle
-radius: double -numberOfObjects: int +getNumberOfObjects(): int +getArea(): double1 radius
circle1 radius = 1 numberOfObjects = 2 instantiate instantiateMemory
25 radius
numberOfObjectsUML Notation:
+: public variables or methods underline: static variables or methods circle2 radius = 5 numberOfObjects = 2After two Circle
objects were created, numberOfObjects is 2. (c) Paul Fodor (CS Stony Brook) & Pearson public class StaticExample{ public intnonStaticCounter= 0; public static intstaticCounter= 0; public StaticExample() { nonStaticCounter++; staticCounter++; public static void main(String[] args) {StaticExampleex;
ex = new StaticExample(); ex = new StaticExample(); ex = new StaticExample();System.out.println(ex.nonStaticCounter);
System.out.println(staticCounter);
16StaticExample.java
(c) Paul Fodor (CS Stony Brook) & Pearson public class StaticExample{ public intnonStaticCounter= 0; public static intstaticCounter= 0; public StaticExample() { nonStaticCounter++; staticCounter++; public static void main(String[] args) {StaticExampleex;
ex = new StaticExample(); ex = new StaticExample(); ex = new StaticExample();System.out.println(ex.nonStaticCounter);
System.out.println(staticCounter);
17StaticExample.java
Output: 1
3 (c) Paul Fodor (CS Stony Brook) & Pearson staticusageCan a staticmethod:
-staticmethod in the same class? directly call a staticmethod in the same class? directly reference a non-staticvariable in the same class? directly reference a staticvariable in the same class?Can a non-staticmethod:
-staticmethod in the same class? directly call a staticmethod in the same class? directly reference a non-staticvariable in the same class? directly reference a staticvariable in the same class? 18 (c) Paul Fodor (CS Stony Brook) & Pearson staticusageCan a staticmethod:
-staticmethod in the same class? No directly call a staticmethod in the same class? Yes directly reference a non-staticvariable in the same class? No directly reference a staticvariable in the same class? YesCan a non-staticmethod:
-staticmethod in the same class? Yes directly call a staticmethod in the same class? Yes directly reference a non-staticvariable in the same class? Yes directly reference a staticvariable in the same class? Yes 19 (c) Paul Fodor (CS Stony Brook) & Pearson1 public class Nothing {
2private intnada;// Errors?
3private static intnothing;
45public void doNada(){ System.out.println(nada);}
6public static void doNothing(){ System.out.println("NOTHING"); }
78public static void myStaticMethod(){
9doNada();
10doNothing();
11nada = 2;
12nothing = 2;
13Nothing n = new Nothing();
14n.doNada();
15n.nada= 2;
16n.nothing= 6;
17}18public void myNonStaticMethod() {
19doNada();
20doNothing();
21nada = 2;
22nothing = 2;
23Nothing n = new Nothing();
24n.doNada();
25n.nada= 2;
26}}20
(c) Paul Fodor (CS Stony Brook) & Pearson1 public class Nothing {
2private intnada;
3private static intnothing;
45public void doNada(){ System.out.println(nada);}
6public static void doNothing(){ System.out.println("NOTHING"); }
78public static void myStaticMethod(){
9doNada();
10doNothing();
11nada = 2;
12nothing = 2;
13Nothing n = new Nothing();
14n.doNada();
15n.nada= 2;
16n.nothing= 6;
17}18public void myNonStaticMethod() {
19doNada();
20doNothing();
21nada = 2;
22nothing = 2;
23Nothing n = new Nothing();
24n.doNada();
25n.nada= 2;
26}}21
(c) Paul Fodor (CS Stony Brook) & PearsonVisibility Modifiers and
Accessor/MutatorMethods
By default, the class, variable, or method can be
accessed by any class in the same package. 22public The class, data, or method is visible to any class in any package. private The data or methods can be accessed only by the declaring class -To protect data!
The get and set methods are used to read and
modify private properties. (c) Paul Fodor (CS Stony Brook) & Pearson23Array of Objects
Circle[] circleArray= new Circle[10];
An array of objects is an array of reference variables (like the multi-dimensional arrays seen before) referenceCircle object 0 circleArray[0]
circleArray circleArray[1] circleArray[9]Circle object 9
Circle object 1
(c) Paul Fodor (CS Stony Brook) & PearsonImmutable Objects and Classes
Immutable object: the contents of an object cannot be changed once the object is created -its class is called an immutable class Example immutable class: no set method in the Circle class public class Circle{ private double radius; public Circle() { } public Circle(double radius) { this.radius= radius; public double getRadius() { return radius; radius is private and cannot be changed without a set method A class with all private data fields and without mutatorsis not necessarily immutable!24 (c) Paul Fodor (CS Stony Brook) & PearsonWhat Class is Immutable?
1.It must mark all data fields private!
2.Provide no mutator methods!
3.Provide no accessor methods that would
return a reference to a mutable data field object! 25(c) Paul Fodor (CS Stony Brook) & Pearson26
Example mutable
public class Student { private intid; privateBirthDatebirthDate; public Student(intssn, intyear, intmonth, intday) { id = ssn; birthDate= new BirthDate(year, month, day); public intgetId() { return id; public BirthDategetBirthDate() { return birthDate; public class BirthDate{ private intyear; private intmonth;quotesdbs_dbs20.pdfusesText_26[PDF] inheritance cycle name of the ancient language
[PDF] inheritance in python 3 tutorialspoint
[PDF] inheritance in python 3.6
[PDF] inheritance in python 3.7
[PDF] inheritance python 3 super
[PDF] inherited uml
[PDF] ini shared path nsclient++ ini
[PDF] initial basic feasible solution in lpp
[PDF] initial basic feasible solution in operation research
[PDF] initial basic feasible solution ppt
[PDF] initialize 2d array in js
[PDF] initialize 2d array java
[PDF] initialize array in jsp
[PDF] initialize array in react js