I have a class A. I have a reference ref of class A pointing to an object of type x.
What kind of object makes ref.getClass() print A$1 ? And what does ... |
Here, it says that:
This gives MountainBike all the same fields and methods as Bicycle, yet allows its code to focus exclusively on the features that make ... |
I have an issue with some inheritance I'm doing. Basically, I have an abstract class called LineCalculator, which, as it suggests, calculates lines of an equation. From there, I inherit this ... |
If i define
class A {
public int a;
public float b;
public A() {
a = 10;
}
}
class B extends A {
public B() {
a = 2;
}
}
class C extends A {
public C() {
b = 2.0f;
}
}
And in ... |
Why does is print last "I'm a Child Class." ?
public class Parent
{
String parentString;
public Parent()
{
...
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I can't remember what it's called when another class's method in java for example in a main class you call the scanner class to scan in user input?
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I am using NetBeans' GUI Designer to create some JDialogs, which I then subclass from my own EditorDialog class.
Before I go further, consider this sample code:
class MyDialog extends EditorDialog {
...
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I'm using an interface in java, pdj, that comunicates my classes with PureData. In order to do so, my classes have to extend a given class (MaxObject). While designing my class, ... |
I have the following code. The angle function needs some information from the class it was called from. What's the best way to do this?
class MyScannedRobotEvent extends robocode.ScannedRobotEvent {
...
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I would like to deprecate only the extension of a given class, not all the methods and fields contained within a class, using the @Deprecated annotation.
That is, a warning will occur ... |
I have a utility class with some static methods which I use in some places around my code. I am facing a problem now. I want to replace the functions in ... |
I'm trying to create a text-based game for class and i'm stuck on trying to get my main class, GCPUAPP, to read from my Artifact class.
Here's the code i've inputed for ... |
I am new in Java so it will be a newbie question, here it is:
I have a class Airplane. But I must have different Airplanes (like PassengerPlane or CargoPlane)
Then I have ... |
I'm training for a Java exam, and I've come across something I don't understand in last year subject. Here is the code
class Mother {
int var = 2;
...
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I write a library with Java interfaces resembling Haskell type classes, and abstract classes implementing all "derivable" methods (e.g. Monad.join can be written using >>= and return). This is ... |
I have to share a String[] across two classes. One class sets the array and the other gets the array. I made four classes. One contains the Array at superclass level ... |
I have two classes, one which is hardware-dependent and one which is not (let's call them HardwareDependent and HardwareIndependent respectively). The Hardware dependent class extends the hardware independent class. ... |
While doing a desing/framework it is a usual practice to have a Base Class for Value Objects, Services, DAOs etc. For example if we create a new VO, it extends from ... |
I have a superclass and child classes.
I am in a child class and in a super method I want to check if a certain parameter object is of the certain child ... |
Is the a way to add a new functionality to a non extend-able class i.e(final class ) in Java , I know a way to add a property to it using ... |
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Of the three classes you've mentioned only two are legal (also watch the spelling on implements) class A extends class B { } class A implements class b{ } In the cases above extends denotes that you are inheriting from a class. implements denotes that you are using an interface. Check out the java tutorial for more information on interfaces. Also ... |
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I have written code similar to what is below. Can anyone explain to me why the instance of class1 created in class2 can't be referenced in class3? class Class1 { private int x; public void setX(int x) { this.x=x; } public int getX() { return x; } } class Class2 { static int blob; public static void main(String[] args) { Class1 ... |
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I have the following scenario: We have a center which is running 3 types of courses: Cooking, Sewing and Writing. Now we want to make sure that our class hierarchy will forbid a user from creating a generic type of course (i.e. not a cooking, or sewing or writing course). Can anybody suggest that how should we implement this? |
Hi Go4Expert o/. I already introduced myself here, but, I lost my account abilondias, and here I am to shot up a question. I am developing a Java Web application and need some instructions. There are 4 classes : Functionary, Donor, Receiver and Manager. All of them have almost the same atributtes. Should I use Java Inheritance or make a class ... |
Hi i have the next task to solve. A bank holds different types of accounts for its customers: Deposit accounts Loan accounts Mortgage accounts Customers could be individuals or companies. All accounts have customer, balance and interest rate (monthly based). Deposit accounts are allowed to deposit and withdraw money. Loan and mortgage accounts can only deposit money. All ... |
Hi, I am developing a program in Netbeans that updates values of a JSpinner when a socket connection comes in. In netbeans, when you create a java desktop application, it creates a Main java class (in my case PolAntApp.java) and the GUI where all Swing stuff is (in my case PolAntView.java). So I went to the main class and did PolAntView ... |
Hi guys! I have this code that I am working on, and when I try to run it, the program goes into a non ending loop and eclipse stalls........ I will post the first class - which is HourlyWorker, and I am supposed to derive a subclass called OTWorker. Hourly worker is derived from "Employee" class, so I hope that does ... |
I want to know if its possible to implement an ArrayList and a LinkedList into a single class ?. What I exactly want to do is this : * Perform addition and removals of elements from the List using a LinkedList. * Perform traversals and searching of elements in the List using an ArrayList . I know this is possible by ... |
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import java.awt.*; public class Building{ int Tile_x; int Tile_y; int Health; Image Picture; Renderer p; public Building(Renderer parent) { p = parent; } public void inital(Image temp_image, int Temp_Tile_x, int Temp_Tile_y, int temp_Health){ Tile_x = Temp_Tile_x; Tile_y = Temp_Tile_y; Picture = temp_image; Health = temp_Health; } // public void draw(){ // p.Buffer.drawImage(Picture, p.Tiles[Tile_x][Tile_y].x, p.Tiles[Tile_x][Tile_y].y, this); // } } |
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Well this is wrong for two reasons. Firstly it was a precondition that A and B didn't have any common supertypes. Nothing says you cannot introduce such supertypes as part of a solution. Secondly I did not introduce any such common supertypes. Both AI and BI are completely separate. CI must inherit both though. If that's not allowed inheritance cannot be ... |
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Hello, I have a kind of conceptual question. Is this conceptually correct to extend a class and not to override any its method? Taking a java collection as an example, would it be OK to create its subclass and just add a couple of methods, leaving all the collection behaviour untouched? Or it would be better design to wrap this collection ... |
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I'd suggest taking a step back, and ask, what's going to be invoking that 3-arg doThis method on B? Generally you overload methods like that for polymorphism purposes so that the caller doesn't need to know what subclass it's getting. The caller just knows that is has an object of type A and by calling doThis, it will do the right ... |
ok two questions. 1. in the java class heirarchy, do the subclasses inherit all of the concrete methods from the superclass, that the subclass has not overridden. Or just some of them as Sun has deemed necessary? 2. In the situation where you have a custom class that extends another class, can you invoke all of the constructors in the superclass ... |
Here i still have to specify a specific class statically, i want it dynamically. I have ProductLists class, which holds the add(), getName() and so on methods. And its all good. But then i want TypeList, BrandList and CategoryList classes to be subclasses of ProductLists class. Because they all hold different kind of information. TypeList class holds for example "Baseball" and ... |
My apologies, I worded that wrong. My current approach (the one given in the code) selects the root package folder. However, what I want to be able to do, is to simply select a single class file. The current code just makes some assumptions so that I can at least see results in the program. As you said, if the root ... |
Is it possible to send a COMMAND to underlying command prompt from JVM? Actually i want to clear the console on which jvm is running. (in simple language i want to send 'cls' command to console). I am using Windows XP & Win2k3 Enterprse server. No. When you open a console window that is an application. In general the term "shell" ... |
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I need to make a bunch of classes for an assignment. Class Person stores the first and last name of the person. Class Student extends from person and also stores the student number. Class Employee extends from Person and also stores the working hours and salary of the Person. Class Instructor extends from Employee and stores nothing extra. Finally I need ... |