polymorphism « Inheritance « Java Class Q&A

Java Class Q&A
1.abstract class
2.Base class
3.class hierarchy
4.class name
5.class version
14.equal method
15.extend Class
19.inner class
21.main class
26.object reference
28.parent class
31.Private Field
35.Static Class
39.Wrapper Class
Java Class Q&A » Inheritance » polymorphism 

1. Force invocation of base class method    stackoverflow.com

The following code when run obviously prints out "B1/A2/B2". Now, is it possible for it to print "A1/A2/B2" instead (i.e. A#method2() should invoke method1() on A, not on B)? Note: I ...

2. Java: Why could base class method call a non-exist method?    stackoverflow.com

class BaseClass {
    private void f() {
     System.out.println("Baseclass f()");

    public static void main(String[] args) {

3. inheritance and class members    stackoverflow.com


class A
    String s = "A";

class B extends A
    String s = "B";

public class C
    public static void main(String[] args){ new C().go();}

4. Polymorphism? Inheritance? How to do it?    stackoverflow.com

EDIT: I know it is a little strange design, and so it is difficult to answer. It Is FlowChart diagram on the picture. Every class represents some type of component used ...

5. Implementation question regarding base classes and derived classes    stackoverflow.com

I have a question regarding the best way to implement this. I'm going to describe my current implementation and how I seem to have painted myself into a corner: I have an ...

6. Using inheritance and polymorphism to solve a common game problem    stackoverflow.com

I have two classes; let's call them Ogre and Wizard. (All fields are public to make the example easier to type in.)

public class Ogre
  int weight;
  int height;

7. Can removing final from a class definition break backwards compatibility?    stackoverflow.com

I'm currently reading Effective Java by Joshua Bloch and Item 17 is 'Design and document for inheritance or else prohibit it'. The author suggest to prohibit inheritance by default. Is ...

8. How was one method chosen over another in this code?    stackoverflow.com

This is another of those SCJP questions. The code below prints Alpha:fooBeta:fooBeta:barBeta:bar, and I don't understand why the first foo call picked Alpha's foo instead of Beta's. If the Alpha.foo parameter ...

9. Java: using polymorphism to avoid if-statements?    stackoverflow.com

I'm attempting to write a java program that initializes certain layouts based on what the user selects. What I want to do is try to avoid writing a bunch of if-statements ...

10. Java Inheritance Issue    stackoverflow.com

Suppose I have the following classes:

class car1 {}
class car2 {}
class car3 {}
class car4 {}
Support I also have the method: queryCar()
private Object queryCar()
     int version = getCarVersion(); // ...

11. java accidential implicit interface implementation    stackoverflow.com

Recently came across an interesting feature, which, though, can result in a unexpected output of Eclipse "add unimplemented methods" feature. What is the "googl-able" name of the language concept behind this ...

12. I'm unable to perform virtual method invocation    stackoverflow.com

This is my code:

class base1

class der1 extends base1
 public static void main(String []args)
  base1 b=new der1();
 public void showTest()
 System.out.println("Hello i am a derive class");

13. Is It Accepted Or Legal To Do this    stackoverflow.com

I have a method in a class say

// super class
public class Car{

    public void printMe(Car c){
          if(c instanceof BMW){

14. inheritance and polymorphism java    stackoverflow.com

I have base class, Customer and sub-classes Acc1 up till 3. When I am reading a file to initialize my array of customer objects, they all just show up as empty. As ...

15. inheritance and polymorphism java    stackoverflow.com

I have an array of objects of my base class, Customer. It has 3 sub-classes Account1, Account2 and acount3. When i run through a loop checking every account for its type ...

16. Please help my OOPS concepts    stackoverflow.com

Okie. I can't believe this is happening but may be some comments from you will help. I have a Parent class.

import java.util.HashMap;
import java.util.Map;

public class Parent {

    Map<String,String> map ...

17. Inheritance problem Low level Design approach    stackoverflow.com

Suppose I have class hierarchy like the one shown in picture. Suppose I need to include a method doThis() that would have different implementation in classes C and D. But the ...

18. Java inheritance structure problem    stackoverflow.com

I have just implemented some classes:

public abstract class Job<T extends ViewerUnion>{

public abstract class ReturnValueJob<T, S extends ViewerUnion> extends Job<S> {

public class MyReturnJob extends ReturnValueJob<Foo, Baa> {

public class JobExecuter {
public static void ...

19. A book for java inheritance and polymorphism    stackoverflow.com

After exploring so many questions on this site about inheritance ,polymorphism, nested & anonymous classes, class inside a interface, nested interface, makable & callback & empty interface ....... i feel that ...

20. What is the main difference between Inheritance and Polymorphism?    stackoverflow.com

I was presented with this question in an end of module open book exam today and found myself lost. i was reading Head first Javaand both definitions seemed to be exactly ...

21. Polymorphism - Call Base class function    stackoverflow.com

Is it possible to call base class function without modifying both base and derived classes?

class Employee {
    public String getName() {

22. Static Method , Inheritance & Polymorphism    coderanch.com

I am not too sure if this is the right forum. Some conceptual questions on object oriented features of java. Are Static methods inherited? I think the answer is yes. Does Static methods support polymorphism? I think the answer is No. What does Java gain by providing inheritance of static methods when you cannot have polymorphism? I have not been able ...

23. New to Java - Inheritance - polymorphism question    coderanch.com

Hi, Below is my scenario! I am doing a code refactor for constant variables declared in two separate A.java and B.java which are to be used in C.java. If condition is true use the constants from A.java or Else use the constants from B.java. So, I thought I could do below class A { final static String s1 = "A"; } ...

25. problem with inheritance / polymorphism    coderanch.com

I've got an incoming XML message. One of the fields inside it tells me what sort of message has to be generated from it, there are currently 5 different ones I've got to deal with, so I've got 1 base class (with a build method) & 5 subclasses for this. I can't think of a nice way to handle the subclass ...

26. Inheritance and Polymorphism    coderanch.com

When an object of the subclass is created on the heap, it will have a place in it for all of the fields that it has and all of the fields that it inherits from when the superclass constructor was executed. So the value of the superclass field is kept IN the subclass object. The subclass does not go back and ...

27. Hierarchies, inheritance, polymorphism and interfaces    coderanch.com

Hi all, I am trying to make some small changes to the version of this code: I want to implement the changes listed below and run it as an application not an applet. I am kind of confused, any help or advice is highly apperecited Bitzack! The changes I wish to make are : 1.The edgeColor data member in class Shape ...

28. Inheritance & Polymorphism    coderanch.com

I created the following program, but am having difficulties. Most notably with the compareTo() method I have to implement. Also when I have to call a superclass. I commented out problems throughout the program. Any help would be great! (it's kind of long). import javax.swing.JOptionPane; public class A2Q1 { public static void main (String args[]){ // An array of Threats Threat[] ...

29. Difference between polymorphism and inheritance    coderanch.com

The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - ...

30. Inheritance and Polymorphism    coderanch.com

Originally posted by Manish Khurana: Overloading is compile time and Overriding is run time i think Overloading is a method with the same name but different arguments (and possibly a different return type). It can be in the same class, or a subclass. Overriding is redefining a method in a subclass. The method must have the same name, arguments and return ...

31. Inheritance and polymorphism    coderanch.com

package pakage1; public class Superclass { void method1() { System.out.println("This is method 1 of Superclass"); } } package package1; import package2.*; public class Other{ public static void main(){ Superclass sc=new Subclass(); sc.method1(); } } package package2; import package1.*; public class Subclass extends Superclass{ } In the above code method1 is not available to Subclass. And sc is instance of Subclass. Can ...

32. whats the difference between polymorphism and inheritence    coderanch.com

An ideal instance of using Inheritance would be when you want to create an entirely new class, but wish to borrow a group of existing attributes or methods resident in an existing Abstract or super Class, instead of re-inventing the wheel. If you had an Abstract Class Carnivore and wanted to create a subclass Cat, you could instantly inherit all the ...

33. Head First Java Inheritance and Polymorphism    coderanch.com

Hello, I`m reading the book, but currently stumbled upon a problem. I always write problems on paper first and then put it to test in the computer, but when i finished and checked the answer it was other than my answers. The first set should print :B's m1, A's m2 , A's m3 (this is correct) The second set should print: ...

34. polymorphism by using interface and inheritance    coderanch.com

public class Pet { private String name; private int age; public Pet(String name, int age) { this.name = name; this.age = age; } public void eat() { System.out.println(name + is eating); } } public interface Mammal { public void breathe(); } //The following Cat class both extends Pet and implements the Mammal interface: public class Cat extends Pet implements Mammal ...

35. Still trying to grasp Polymorphism and Inheritance    java-forums.org

abstract class Family { private String name; public void someMethod() { //...Some code here to do stuff } protected void setName(String string) { name = string; } } public class Dad extends Family { public Dad() { } public Dad(String string) { setName(string); } public void methodA () { //...code here to do stuff } }

37. Help with Inheritance and Polymorphism    forums.oracle.com

6. Make sure that your code includes proper toString() methods in both classes defined in the requirements 5.a. and 5.b. to provide the inventory display in the following format: a. One record per line. b. Each line is formatted according to the layout below. Columns Field name 1 - 10 SKU (stock keeping unit a unique item identifier) 11 - ...

38. Inheritance and Polymorphism problems    forums.oracle.com

39. Inheritance and Polymorphism    forums.oracle.com

40. Problem about Inheritance and Polymorphism    forums.oracle.com

41. Inheritance Polymorphism    forums.oracle.com

The way that I think about this is that p is a parent variable and though it refers to a child object, it can refer to a parent object or any of its children, and this reference can change during the lifetime of the program and the compiler will have no knowledge of this. Thus Java is designed to not allow ...

42. Inheritance and polymorphism questions    forums.oracle.com

Output: If account is created display pin code, first name, last name, the type of account, the amount in the account. If the option chosen was withdrawal/deposit you will need to display the Pin code number, last name, first name, deposit/withdrawal, charges if incurred, and the balance in the account I have created an abstract (Account) class along ...

java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.