inheritance 2 « Inheritance « Java Class Q&A

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Java Class Q&A » Inheritance » inheritance 2 

1. Appropriate use of inheritance    coderanch.com

We have many Database Access Classes (D1, D2, D3...) for each table in our application. All of these classes need to access some common functions such as getConnection and getResultSet. I suggested keeping these functions in a separate Utility Class. The concern in the team is if we do so we will instantiate several objects of the Utility class as all ...

2. Why need of inheritance???????    coderanch.com

Hi, This question is regarding the concept of inheritance! Suppose that there are 2 cases CASE 1: class A { // some members in this class } class B extends A { // some members in this class } here we are able to get all the members of the class A in Class B. CASE 2: class A { // ...

3. Inheritance nightmare.    coderanch.com

Inheritance nightmare. (Java in General forum at JavaRanch) A friendly place for programming greenhorns! Register / Login Java Forums Java Java in General Inheritance nightmare. Post by: Ken Blair, Ranch Hand on Dec 09, 2005 18:14:00 EDIT: If you're just visiting this (convoluted) thread you may want to skip down a few posts before you start reading. I'm writing ...

4. What is Inheritance    coderanch.com

5. Inheritance in Bytecode!    coderanch.com

Hi Everyone, Am just curious about the way subclasses and superclasses are paired after compilation in byte code. For instance, if we have a superclass called HugeSuperClass and numerous subclasses inheriting its many members, then does the relationship between the superclass and subclass still exist in byte code where the JVM during interpretation goes on fetching bits and pieces from all ...

6. Inheritance concepts    coderanch.com

Can somone please explain the Inheritance concepts in the following code. What values are printed and how the Compiler chooses the values and methods to be executed. What if the base instance-variable/method is static and the Derived variable/method is static. class Base{ public int x=3; public Base(){} public void show() { System.out.println(" base x is " + x); } } Class ...

7. Inheritance structure and polymorphic designs    coderanch.com

Hi everyone, I am hoping for some advice regarding inheritance. Currently I am working in a system incorporating employees of various types. The base class is Employee, with other classes in the hierarchy requiring additional functionality and extending this class. My question is one of good design. What is the best way to represent this relationship while allowing the type of ...

8. doubt on mutiple inheritance    coderanch.com

Here's how I justified it in my own mind just so I could go on with life ... If you implement two interfaces with the same method signature and you decide they both have the same semantics you can implement one method to satisfy them both. If you decide they don't have the same semantics you probably shouldn't implement both. If ...

9. confusion in code regarding inheritance according to java5    coderanch.com

Originally posted by Rajesh Pitty: so how does the compiler go about this. This is only hard to imagine if you think of a compiler as a sort of translator that turns each symbol in a Java source file into a few bytes in a .class file, one after the other, in order. It doesn't work that way at ...

10. Inheritance issue    coderanch.com

11. Inheritance heirarchy    coderanch.com

class base { String s="jai"; Object o=s; Object k=new Object(); String h=(String)o; String s=o;/* can this be done? */ } In the above coding.what is the difference between objects o and k.What will be the pointing.?Can i cast the object o to a string?If so what will be the contents of the objects o and h..?

12. Inheritance Doubt    coderanch.com

Hi guys, I was experimenting earlier. Why is it that we are allowed to redefine another member of the same type and name of that in an abstract class? public abstract class A { int i; public int getI() { return i; } } class B extends A { int i; public int getI() { return i; } } What happens ...

13. Inheritance Question    coderanch.com

Originally posted by Sanjay Gurav: Hi, "Sorry Its Polymorphism Question" Classs AA{ public void sample(String s) { System.out.println("String"); } public void sample(object s) { System.out.println("Object"); } } Class BB{ public void static main(String str[]) { AA a=new AA; a.sample(null); } } What will be the output if we compile and run please explain me. Thnx, Sanjay :roll:

14. Inheritance problem    coderanch.com

Exactly!!! I thought copy of public methods are made and put into subclasses. But it seems that when i call a certain inherited (non-overridden) method from a subclass, then the method of superclass is called and it operates on the variables of superclass only. I think a major confusion is resolved. Thanks. But some confusion is still lying. What you are ...

15. Doubt about Inheritance and Coupling    coderanch.com

Hi there, here is a question that I have not able to answer correctly, so I would appreciate any help: Assuming that this definition of coupling (or dependency ) is correct ( => "the degree to which each program module/class relies on each one of the other modules/classes") Can we say that if we define a inheritance relationships between 2 classes ...

16. inheritance (need help)    coderanch.com

code: package a; public class Father{ //some code... } ------------------------------------------------------------------------- package b; import a.Father class Son extends Father{ Father a= new Father(); // compiler good. } --------------------------------------------------------------------- However if son class like this package b; class Son extends a.Father{ Father a= new Father(); // compiler error! } So, what's the difference between these two son class. I tried if not use ...

17. Inheritance in Java    coderanch.com

Hi, I want to know following: I have three classes. Parent.class child1.class child2.class Public class Parent extends Applet{ public void init() { child1 c1 = new child1(); child2 c2 = new child2() } } public class child1 { public void send() { x = a+b; } } public class child2 { public void getValue() { QUESTION: I want to access the ...

18. Inheritance    coderanch.com

class Base{ int i=100; void show(){ } } class Derived extends Base{ int i=10; void show(){ } When i say Base b=new Derived(); b.show(); System.out.println(b.i); b.show(); calls the method of the Derived class that's ok.But why b.i is bringing Base variable value. & not Derived one. When we say Base b then b refers to class Base & when we say ...

19. ?(inheritance) from a newbie    coderanch.com

Hi! I'm reading peter van der linden's book. I have these 2 classes... class Fruit { String zesty = "Fruit String"; void doThis() { System.out.println("Fruit Method"); } } class Citrus extends Fruit { String zesty = "Citrus String"; void doThis() { System.out.println("Citrus Method"); } public static void main(String args[]) { Citrus c = new Citrus(); Fruit f = c; c.doThis(); //displays ...

20. inheritance thru upcasted reference    coderanch.com

BaseClass bc = new DerivedClass(); bc.protectedMethod(); In the above given code the BaseClass is the parent of derived class and protectedMethod is protected in Base Class And this code is placed in a instance method of the derived class. Why do i get a compiler error ........ " Can't access protected method protectedMehod in BaseClass. BaseClass is not a subclass of ...

21. Inheritance    coderanch.com

Let me try to explain best I can. I have created a bunch of classes(10). Each class has many different methods but they all have the same method named: getMyColor() So, in another class I need the constructor to have one of the possible 10 classes I created. I built the constructor like this class newClass(Object x) { x.getMyColor(); // error ...

22. inheritance    coderanch.com

So you mean can you stop being a subclass or a superclass suddenly? No, at least not dynamically - as you are executing. Class A can PREVENT subclassing by being final. like "public final class Math" And if it was not final, and there is a subclass, if you stop and make the super class "final" and recompile, and then try ...

23. inheritance    coderanch.com

24. Inheritance.    coderanch.com

Hi. I created this code and compiled it. import java.io.*; class Super { private int java, ranch ; public Super() { } public Super(int r, int s) { java = r; ranch = s; } int methodOne( int a, long b ) throws IOException { // code that performs some calculations return a; } float methodTwo( char a, int b ) ...

25. Inheritance help    coderanch.com

I have trouble understanding why this is so... class A { String name="Class A"; void mutate() { name="Class A"; System.out.println("Method in Class A invoked"); } } class B extends A { String name="Class B"; void mutate() { name="Class B"; System.out.println("Method in Class B invoked"); } } class TestClassAB { public static void main(String[] args) { ClassA obj = new ClassB(); obj.mutate(); ...

26. inheritance    coderanch.com

27. Inheritance - weird behaviour ?    coderanch.com

I have this piece of code: public class A { public static void main(String[] args) { Child c = new Child(); c.f(); //1 } public static void pr(String s){ System.out.println(s); } } class Parent{ public Parent() { A.pr("Parent::constructor"); } public void f() { f_(); } public void f_() { A.pr("Parent::f_"); } } class Child extends Parent{ public Child() { A.pr("Child::constructor"); } ...

28. inheritance and contstuctors problem    coderanch.com

I had a weird problem today. I was experimenting with a framework library and came across a compile-timer error that deals with inheritance and constructors. I wrote up the following code to demonstrate the problem: import java.util.Hashtable; public class DBQuery extends DBObject { String query = "select emp.name from emp, company where company.name='Greedy, Inc.'"; public String runQuery() { DBConnection conn = ...

29. Question on Inheritance syntax    coderanch.com

The following code gives the errors listed below it. I have found some work arounds, but am wondering why this doesn't work. Can someone explain? - Rob ----- Begin Code ----- import java.util.*; public class FooBar { public static void main( String[] args ) { Foo foo = new Foo( "Hello, world" ); System.out.println( foo.getBar() ); } } class Bar extends ...

30. Inheritance help    coderanch.com

I have a problem I wrote a class ResSearchTree that extends another class BinarySearchTree that resides within a package. Also in the package is a class called BinaryNode. I wrote an extension of this called ResNode. Then in ResSearchTree, I proceeded to override inherited methods to accept an instance of ResNode instead of BinaryNode. example : ( Overridden insert method) protected ...

31. Why no mutiple inheritance    coderanch.com

Hi, One of the major benefits of OOP'S is reusability. This is achieved using inheritance. Unfortunately Java does not support muliple inheritance. Suppose I want to extend 2 classes A,B in java and create a class called C, it is not possible. I can only extend one class say A but for B I have to copy all methods and variables ...

32. inheritance problem    coderanch.com

Originally posted by Lucious Mucas: Unless you are creating a nested class then you need to take the class out of your constructor. Your constructor should look something loke this: //declaring class public class Example { //declare global variables .... //intialize global variables with constuctor public Example { globalVar = 0; }//end constructor }//end class

33. Inheritance program    coderanch.com

34. has-a and is-a (inheritance)    coderanch.com

Here is the code that someone showed me to explain it. public class Vehicle { protected Motor motor ; } public class Car extends Vehicle { private Tire tire ; private Trunk trunk ; } public class Motor { } public class Tire { } public class Trunk { } All vehicles have a motor so the vehicle has a member ...

35. Inheritance Problem    coderanch.com

public class A{ static public void method1(){ System.out.println("method a:1"); } public void method2(){ System.out.println("method a:2"); } } public class B extends A{ static public void method1(){ System.out.println("method b:1"); } public void method2(){ System.out.println("method b:2"); } } public class tmp { public static void main (String[] args){ A a = new B(); a.method1(); a.method2(); } } Output method a:1 method b:2 Could ...

36. Basic Inheritance question    coderanch.com

just a newbie here trying to understand inheritance. Here's what I've deduced so far portrayed in an example: Let's say we have 3 classes: Animal (superclass), Dog, and Cat. Classes Dog and Cat are inherited from Animal. Now let's say that in my main method, I declare 3 objects: Animal animal; Dog dog; Cat cat; It would be "legal" for me ...

37. inheritance question    coderanch.com

Hey SteveO, Well, you generally use an interface to define a common behavior among unrelated classes. For example if you had a Person class and a Car class with no common ancestors, they could both implement an interface Wash since both occasionally need to knock off the trail dust. Inheritance or extending a class on the other hand involves classes with ...

38. Inheritance    coderanch.com

Dear all, I read from some materials that all members of a class are inherited. Is it really true for private members. If it does, that means the subclass will also contain the private member from the superclass. Therefore, the subclass should be able to access it, say from within the subclass itself. Actually, it is not. When I access the ...

39. problem with inheritance    coderanch.com

40. Inheritance in a problem...    coderanch.com

Hello. I have this problem that I am working on. I have to re-write a Point-Circle-Cylinder program into a Point-Circle-Cube program. Here is all the code that I have developed. How do I combine it in order to run this program using all the code? I am confused as to how to put it together so it will work... Thanks... // ...

41. Multi level inheritance.    coderanch.com

Do you mean multiple inheritance? If so, preventing multiple inheritance avoids many of the associated problems such as where D extends B and C both of which extend A. If you call a method on D which is implemented in B and C, which implementation do you choose? Multi level inheritance (e.g. C extends B extends A) is allowed.

42. difference between abstraction and inheritance    coderanch.com

Abstraction is loosely defined as the opposite of attention (to detail). So, for example, the speedometer in a car is an abstraction of the device that actually tells you the speed. You do not need to know about the fact that there is a rotating magnet that is picked up by a sensor every time it passes a certain point and ...

43. Two stupid questions about inheritance    coderanch.com

I have some questions about inheritance.In fact,I'm not really familiar with inheritance in java.Mabye my concepts are wrong,please correct my idea. Question1: class Animal{ Animal(){SYstem.out.println("Animal()");} } class Bird extends Animal{ Bird(){System.out.println("Bread()");} } class parrot extends Bird{ parrot(){System.out.println("parrot()");} } class fish{ fish(){System.out.println("fish()"); } class zoo extends parrot{ fish f=new fish(); zoo(){ System.out.println("zoo()");} public static void main(String[] args){ new zoo(); } We know ...

44. Proper Structure Question / Inheritance & Casting    coderanch.com

Hey everybody, I originally posted this to the intermediate forum, but I'm feeling like perhaps the answer is so simple and obvious that I should have posted it in the beginner forum: my original post in the intermediate forum. I'm sorry for cross-posting; I'm aware that it's bad netiquette -- but please have mercy, I feel like perhaps the question belonged ...

45. Help with an Inheritance issue    coderanch.com

Ok, I'm getting some errors in my SalesEmployee class which extends Employee class. The error has to do with a variable that isnt in the employee class called "managerName". Its in the SalesEmployee class because thats how the teacher wants it. Did I declare it wrong in my SalesEmployee class or what am I doing wrong. Here is my SalesEmployee class ...

46. Can't resolve symbol in inheritance    coderanch.com

OK I don't understand why I get a can't resolve symbol on my constructors. Here is the basics of my code 3 classes - 1st class 'A' is abstract has a default empty constructor and a constructor with A's attributes ex: public A( int getX ) { this.x = getX; } 2nd class B extends A and has default empty constructor ...

47. inheriting an innerclass    coderanch.com

48. Question about inheritance    coderanch.com

Hi. I'm currently working on a final project for AP Computer Science 1 and have question about inheritance. If the superclass were to have try and catches, will the subclass inherit those characteristics? (Code provided below). If this is possible, could someone show me how to make FilesoundFile = new File("C:\\WINNT\\Media\\notify.wav"); into a method or somehow other classes able to change ...

49. inheritance homework assignment - im stuck    coderanch.com

Greetings all, this is my first time here. Since the class I am taking is considered an intro / beginning java class, I figure this forum would be appropiate for my question. Please note that I am not looking for somebody to do my work for me, rather I am looking for some pointers as I seem to be lacking the ...

50. Doubt in Inheritance    coderanch.com

Hi all , This my example program. It may be silly doubt, please tolerate my ignorance class A { public void methodA() { System.out.println("Method 1"); } public void methodB() { System.out.println("Method 2"); } } public class B extends A { public void methodC() { System.out.println("Method 3"); } public void methodD() { System.out.println("Method 4"); } public static void main(String args[]){ B b= ...

51. Inheritance question    coderanch.com

Jeff, Another important concept to consider is the fact that inheritance is an "is-a" relationship. For example, a Cat is-a Animal so it is appropriate for Cat to extend Animal. The animal superclass might contain some methods such as eat(), drink(), sleep() and many others that are appropriate for Cat and other subclasses of Animal. The Cat class might contain new ...

52. inheritance    coderanch.com

The true power of inheritance is polymorphism. Consider a parent class called Animal, and suppose it has a method called transportOffspring(). In this Animal class, the implementation of transportOffspring() might be to simply herd the offspring. Now consider two classes that each inherit from Animal: One is Cat, which overrides transportOffspring() to carry by the scruff of the neck; and the ...

53. Question regarding Inheritance    coderanch.com

Well first of all, I'd like to comment on what a great board and site this seems to be. Everyone seems very helpful and the information is well organized. Not just asskissing, I mean it. Now onto my question. I am trying to extend a class called Polygon: public class Polygon { protected int side1; protected int side2; protected int side3; ...

54. Basic Inheritance Question    coderanch.com

Hi all, I am preparing for JCP. This is a very preliminary question Here is my sample code class trial{ private int test=10; int test1=20; int trying() { return test; } } class B extends trial{ int test() { int k=super.test1; return k; } void value(){ System.out.println("this is the value test"+super.trying()); } } class inheritclass{ public static void main(String args[]) { ...

55. Inheritance    coderanch.com

I'm constructing a StandardDeck class that inherits from a Card class. I've compiled my code and am receiving the error "Card(int,int) in Card cannot be applied to()." Does anyone know what this means? Here is my code for the StandardDeck class: import java.util.ArrayList; public class StandardDeck extends Card { private ArrayList a = new ArrayList(); private int iMyNumCards; public StandardDeck() { ...

56. Inheritance Issues    coderanch.com

Greetings to everyone. To me inheritance does not seem like a beginner issue, but this is encapsulated in a introductory course. I really feel like I am asking someone to teach me Java from scratch, but some of the basic stuff I feel I dont understand. Anyone who can help I greatly appreciate. My issue is much bigger than what I ...

57. More Major Inheritance Stuff.    coderanch.com

Greetings to everyone. I am pasting most of the same letter I had last time because I am having the same issues. I am on a time frame if you guys can help. To me inheritance does not seem like a beginner issue, but this is encapsulated in a introductory course. I really feel like I am asking someone to teach ...

58. inheritance    coderanch.com

To my suprprise the code below gives as a result 5, sub. Does anybody know he rule behind this? class Super { int index = 5; public void printVal() { System.out.println( "Super" ); } } class Sub extends Super { int index = 2; public void printVal() { System.out.println( "Sub" ); } } public class Runner { public static void main( ...

59. Inheritance pbs    coderanch.com

First, use code tags when you post code. (look below next to all the little faces as your posting) In your code the method 'coolMethod()' has a return value of void, it doesn't return anything, so it can't be concatinated to the string on line 1. I think what you want to do is return "Hello" rather than System.out.println("Hello")

60. inheritance doubt    coderanch.com

You can define a variable of the abstract type and make it refer to an instance of a concrete type. public class Person { private Contrato contrato = null; public void setContrato( Contrato a ) { contrato = a; } public Contrato getContrato() { return contrato; } } All that compiles and runs when other classes call with an instance of ...

61. Inheritance    coderanch.com

Looks like a typo in TIJ. When you subclass another class you have (not just have access to, but have in your new class) all the public and protected members (variables and methods) of the super class. Static members are an exception, you still have access, but they are not a part of your class.

62. A little help with my homework, explaining inheritance    coderanch.com

Hi, I have homework due for my class and I got the swing design down but am really confused with the specifications of the homework. I'm still reading about inheritance so the assignment is a bit past my skill level. If someone could explain it in a simpler method that would be awesome! Unfortunatly the case only meets once and week ...

63. Inheritance , dynamic binding?    coderanch.com

class Vertebrate{ public int a = 1; void move1(){ System.out.println("MOVE"); } } class Mannal extends Vertebrate{ public int a = 2; void move2(){ System.out.println("walks"); } } class Dog extends Mannal{ public int a = 3; void move3(){ System.out.println("walks on paws"); } } class TestI{ public static void main(String[] args){ Dog d = new Dog(); Vertebrate v = new Vertebrate(); v=d; d= ...

64. What's best practice in this inheritance case?    coderanch.com

imagine i'v these classes: package foo; public class Person { private String name; // or protected? public void setName(String name) { this.name = name; } public String getName() { return name; } } package foo; public class TaxPayer extends Person { private String TaxPayerId; public TaxPayer(String name, String TaxPayerId) { this.name = name; // name not visible this.TaxPayerId = TaxPayerId; } ...

65. Inheritance help    coderanch.com

I am learning about inheritance and for the most part I understand all the concepts along with polymorphisms. What I don't understand is how these ideas fall into building a real world application. If someone could, please point me to some code examples that embrace inheritance and polymorphisms. I would like to see how they work in a large application/program. Don't ...

66. inheritance question    coderanch.com

67. Inheritance problem    coderanch.com

This is a problem that i am working on is based on inheritance concept. I am having trouble in the action performed portion of the code. The problem is to create an applet that has a button (JButton) labeled Change, a red circle and a green square (each 50 pixels across). Each time the button is pressed, the circle grows by ...

68. Inheritance problem    coderanch.com

I am having some issues learning inheritance. I have stumbled across this example in my book but it has got me floundered. I am not expecting a resolution to this but maybe a little push in the right direction. I need to write an inheritance hierarchy for classes quadrilateral, trapezoid, parallelogram, rectangle and square. Quadrilateral bieng the superclass of the heirarchy. ...

69. inheritance - flow    coderanch.com

70. Dynamic Inheritance    coderanch.com

Some less strongly typed languages let you change the parent class of an an object at runtime. I was just reading about this yesterday in ECMAScript aka JScript where you can change the template (parent class) on the fly. THIS ARTICLE claims to do dynamic inheritance in Java but it's just using a Factory Method and not changing anything about a ...

71. Inheritance ?    coderanch.com

'G' - the guys here are trying to encourage you to think a little bit first. Before you know the disadvantages of something, you need to know a little bit about it, right? 1) What are some features of Java? What were some of the design goals? 2) What are some features of inheritance? What does it try to achieve? Are ...

72. Initialization with Inheritance    coderanch.com

I'm trying to work out in which order elements of a class are loaded. 1. Static field variables 2. Regular field variables 3. Constructors For example: If I have the following classes. class Grandad { private int age = 65; // [a] public static String generation = "Oldest"; // [b] public Grandad {} // [c] } class Dad extends Grandad { ...

73. Is this inheritance?    coderanch.com

I was hoping someone could set me straight on this inheritance / abstract class question. (Courtesy of Bruce Eckels Thinking in Java, again). I have a private abstract static class Tester as an inner class in my ListPerformance class. As another variable, I have an array of Tester objects which receieve new anonymous classes as parameters. Since you cannot instantiate an ...

74. What Inheritance Actually Do    coderanch.com

We Have two Classes A and B a is a method in A b is a method in B When we inherit Class A into B After that we create a object referance to Class B Then what happend in heap area. Whether two objects are created or only object is created for B

75. Inheritance casting    coderanch.com

Originally posted by jiju ka: A narrowing conversion is not detected at compile time. It is detected only at runtime. At Runtime you will get a ClassCastException. In the above code you can see that an instance of Object is wider than an instance of A. Similarly A is wider than B. But the compiler don't know about which type is ...

76. Help on Inheritance    coderanch.com

Dear All, I have been learning Java for a while now and I have run a few successful snippets on inheritance using extends keyword. But suddenly now I get the following error on running the subclass. This is a sample picked up from the java site directly. Could some one tell me what I am doing wronog? I am using textpad ...

77. Inheritance    coderanch.com

78. inheritance question    coderanch.com

Hello Hunters; I am trying to implement inheritance in my application and here is the deal. I have a Tag class that gets data tag etc. as its constructor, and I have a displayTag class which I want to both be subclass of my Tag class so that it could get the variables and methods that Tag have and plus I ...

79. inheritance from more that once source....    coderanch.com

ok, maybe im just retarded, but i have a main file that draws and stuff....and has the listeners, the other file i want to make only would have methods that are in my main file right now, the only reason i want to make a separate one, is to clean up my main file a lil. cause i know you can ...

80. Muliple inheritance    coderanch.com

Although the responses are correct, there is more to the story than that. In the early 1990s, before Java was released, C++ was the dominant OO language for development, and it went through some growing pains. One of the problems compilers ran into was how to properly represent multiple inheritance that a)worked, and b)was relatively efficient. Multiple inheritance, it turned out, ...

81. Confused about Inheritance (I think)    coderanch.com

Hi Al, Welcome to JavaRanch! This isn't a very friendly API you're using is it? The public constructor actually just looks like a mistake if there are no other public instance methods; extending the class or creating an instance of the class isn't going to do anything useful. Instead, what you could do is actually call the "main" method directly: void ...

82. inheritance question (I guess)    coderanch.com

Hello I am trying to extend my muscle class with spring class. so in my spring constructor I have this: class spring { int type;// spring type float restLength; // spring restlength float softLength = 0; // springyness int A, B; // particles that spring connects particleSystem parent;// our reference particleSystem public PApplet p;// mom. public spring(PApplet $p, particleSystem $parent, int ...

83. Initialization and Inheritance    coderanch.com

I am working on an exercise to explain the process of initialization in an inheritance context. This this the program I wrote and the explaination of the process. Will someone please comment if I am on the right track. Thank you in advance. class Manager { private int i = 2; protected int j; Manager() { System.out.println("i = " + i ...

84. about inheritance    coderanch.com

85. Polymorphy & inheritance    coderanch.com

public class Tierbesitzer { public void start() { Hund h1 = new Hund(); h1.setGrsse(5); Hund h2 = new Hund(); h2.setGrsse(12); Katze k1 = new Katze(); k1.setGrsse(2); Katze k2 = new Katze(); k2.setGrsse(19); Tierarzt arzt1 = new Tierarzt(); arzt1.gebeSpritze(h1); arzt1.gebeSpritze(h2); arzt1.gebeSpritze(k1); arzt1.gebeSpritze(k2); } public static void main (String[] args) { Tierbesitzer neuerBesitzer = new Tierbesitzer(); } }

86. Inheritance question    coderanch.com

I'm trying to create one instance of a file type (txt, jpg, doc, etc...). I have an inheritance structure that goes something like this. abstract FileClass <- superclass JPG DOC TXT <- (child classes) Ignore the fact that this example doesn't seem very practical, it's more for just learning inheritance. I have a swing menu where I can select to load, ...

87. java inheritance    coderanch.com

Originally posted by subhakar edeti: every body aware object class is super class of every class in java. means every class extends the Object class. class A extends B{} already extends Object class in this a can have properties of both object and b class how this is posible even though java doesn't supprot multiple inheritance.

88. Inheritance and Boolean conditions    coderanch.com

Could someone take a look at this code and offer some insight as to what I might be doing wrong? I can't figure out how to add the $220 for the wireless card. Here are the instructions for the problem: A class Computer has the following: Fields: String manufacturer; float price; int memory; int diskSize; Constructors: Computer(){} Computer(String , float , ...

89. Inheritance Doubt #1    coderanch.com

Hi guys, I was just trying a program in eclipse. The dbt is, why does the parameterized constructor in the sub class need to make an implcit call to the non-parameterized constructor in the super class ? e.g :- public class SuperClassA { String superIdentity; static int noOfClassAObjects = 0; SuperClassA(String identity) { noOfClassAObjects++; this.superIdentity = identity; } void whoAmI() { ...

90. inheritance question    coderanch.com

thanks, marc weber. I can undertsand the article. If myDog.sayHello() results "Dog says Hello", I can understand the theory behind. But my doubt is a new Dog instance is created, and it implicitly got "super();" in its constructor, then inside Animal class constructor, it calls sayHello method. Why and how this superclass (Animal) knows to call its subclass (Dog)'s method, sayHello()? ...

91. doubt in inheritance    coderanch.com

i am arulraj and have a doubt in inheritance.. please see the following example. class A { int a=10; } class B { int a=20; } A objA=new A(); B objb=new B(); objA=objb; // 1 objb=objA // 2 it says compiler an error. In the above example , if you assign a subclass object to a superclass object, the program compiles ...

92. inheritance doubt    coderanch.com

93. inheritance problem    coderanch.com

Here's a strange one for you... I'm into inheritance now in this book, and my constructors clearly send 2 and 3 double arguments to the Square and Rectangle classes, respectively, but their values are 0, according to the system.out statements I have in the program. Anyone have any idea why? Parent class: package ch11; public class Square { double height, width; ...

94. help needed with inheritance    coderanch.com

Hello, I have a class called Car and a main class that implements this class. Both are pasted below. I expect the implementation to print out the price of the car but it is giving me price '0'. Can anyone please advise as to what I am doing wrong. Would be extremely thankful. Ricky package InheritanceHW; public class Car { int ...

95. Inheritance    coderanch.com

Hi, I'm doing a test, and I need to write a set of classes that represent a Circle, Triangle and Rectangle, and then allow user to find the area of any of them. I,ve added a 'name' field too, my plan is to just use an abstract class Shape, and let the others extend it, please can you tell me if ...

96. Doubts about Inheritance    coderanch.com

Hi, I'm from Brazil. First of all, sorry my English. I'm studying Head First Java, of Kathy Sierra and Bert Bates. So, chapter 7 (I guess) is about Heritage (superclass and subclasses) and here's the quote: Private members are not inherited Public members are inherited But, take look at my 2 codes. First one, the superclass: public class Superclass { private ...

97. This is a good one about inheritance    coderanch.com

class Base{ int value = 0; Base(){ addValue(); } void addValue(){ //This method value += 10; } int getValue(){ return value; } } class Derived extends Base{ Derived(){ addValue(); } void addValue(){ value += 20; } } public class Test3 { public static void main(String[] args){ Base b = new Derived(); System.out.println(b.getValue()); } }

98. inheritance    coderanch.com

Java doesn't support multiple inheritance because of Deadly Diamond of Death Lets take an example: 1)take notebook and a pencil and start making a diagram 2)Suppose we have one class A, with method printMe() 3) We have two subclass B and C,Both inherits A,both Override printMe() A B C connect them by arrow. 4) we have one more sublclass D, Now ...

99. multilevel inheritance in java    coderanch.com

100. Inheritance    coderanch.com

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