problem about overriding-Collection of common programming errors

• 
  Anders Abel
  c++ virtual overriding
  I wanted to have confirmation about the following things:Virtual Mechanism:I f I have a base class A and it has a Virtual method, then in the derived class generally, we do not include the virtual statement in the function declaration. But what does a virtual mean when included at the dervied class definition.class A { public: virtual void something(); }class B:public A { public: virtual void something(); }Does, that mean that we want to override the method somethign in the classes that derive
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  Buhake Sindi
  java polymorphism overriding
  Polymorphism allows the programmer either to inherit, override or to overload an instance method of Parent Class. But, it won’t allow to make an instance method of parent class as more restrictive in child class. i.e it wont allow to use same name of parent class instance method, to declare as private in the child class.Also JVM identifies the parent class version of an instance method, if child class didn’t override it.Similarly why don’t JVM identifies the parent class version of an instance m
• 
  Fernando
  objective-c cocoa overriding strong-typing loose-typing
  I have a class called AddressCard from an example in “Programming in Objective C”, and I’m implementing a isEqual: method.The signature of this method in NSObject uses loose typing for the parameter:- (BOOL)isEqual:(id)anObjectOTOH, the sample code in the book uses strict typing:- (BOOL) isEqual:(AddressCard *) aCardI’m not sure I fully understand what the compiler does in this case. I tried comparing an AddressCard to a NSString ([aCard isEqual: @”Foo”]) expecting either a runtime error (if the
• 
  Andry
  .net inheritance f# overriding
  The question is simple and. although it is obvious the answer, I had to face a strange situation where the fsharp told me something a bit strange. Here’s the story:The question is: Does F# automatically make every type inherit the Object class? I suppose YES and I am certain of this because there would be so many complications if that were not the case.But here’s a fact. I was writing this piece of code:type MyType =val myval: intoverride self.ToString = “Hello MyType”Well, fsharp compiler told
• 
  the Tin Man
  c++ python ruby overloading overriding
  Where in the process of creating the program, compiler, linker etc., is the overriding of functions and operator overloading done?I’m particularly interested where it is done in C++, Ruby and Python.
• 
  Chris Farmer
  java class inheritance overriding
  Ok, maybe this is a stupid question. But i’m just wondering if this can be done in java.abstract public class ParentClass<T> { abstract public T getTest(); }in the subclasspublic class SubClass extends ParentClass<MyObject> {public MyObject getTest() {// I can return the object with class MyObjectreturn null;} }My question is can I return the class type in the child method? I mean, is it can be done by adding some code in the ParentClass, so I can do this below?For examplepublic cl
• 
  Jomoos
  java polymorphism overloading overriding method-dispatch
  I do know the syntactical difference between overriding and overloading. And I also know that overriding is run-time polymorphism and overloading is compile-time polymorphism. But my question is: “Is overloading is really compile-time polymorphism? Is the method call really solving at compile time?”. To clarify my point, let’s consider an example class.public class Greeter {public void greetMe() {System.out.println(“Hello”);}public void greetMe(String name) {System.out.println(“Hello ” + name);}
• 
  Zoran Zaric
  java serialization overriding
  I override a createSocket() method in my test cases to pas in a mocked Socket. After doing this the objects aren’t serializable anymore.Here’s a example of what doesn’t work.Foo.javaimport java.io.Serializable;public class Foo implements Serializable {private static final long serialVersionUID = 3109852436898487119L;public void bar() {System.out.println(“Foo”);} }FooTest.javaimport java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.ObjectOutputStream;import junit.framewor
• 
  Paulo Ebermann
• 
  Hesam
  java methods overloading overriding
  I was testing a code when I faced something strange that I could not figure out why this is happening. So I will give a simple example of what happened there.Consider these classespublic class A {public void print(A a) {System.out.println(“A”);} }public class B extends A {public void print() {System.out.println(“B”);} }public class C extends B {public void print(A a) {System.out.println(“C”);} }public class E extends C {public void print(E e) {System.out.println(“E”);} }Now in my main method I h
• 
  pencilCake
  c# interface static abstract-class overriding
  I have one abstract class -let’s say myBase. And I want all the classes derived from myBase to have one static field called public static List<string> MyPArameterNames { get {return _myParameterNames;} }So, every child class can tell what parameter names it uses; I want static because I do not want to create an instance just for this.How can I achieve this?
• 
  Bhesh Gurung
  java android inheritance override overriding
  Possible Duplicate:When do you use Javas @Override annotation and why? Newbie question – I’m writing my first Android app (its my 2nd Java app). I noticed that in examples the onCreate() method has the @Override annotation, but I haven’t used that annotation and it seems to work fine.Is it just good practice to use the @Override annotation or am I setting myself up for problems. What about the other inherited methods – onPause etc?
• 
  Perception
  java deprecated overriding
  I want to remove a method from a class that is present in it’s super class. I can deprecate the superclass method using the @Deprecated annotation, but it is still accessible in the subclass.Eg: public class Sample {void one() {}void two() {}@Deprecatedvoid three() {} }class Sample2 extends Sample {@Overridevoid one() {}public static void main() {Sample2 obj = new Sample2();obj.one();obj.two();obj.three();// I do not want to access this method through the sample 2 object.} }While using the Sampl
• 
  Jigar Joshi
  java oop polymorphism overloading overriding
  I have been coding few examples on method overloading and method overridng. Method overloading is static polymorphism and overriding is dynamic polymorphism.So any error related to overloading will be caught at the compile time..Correct ?or are there any scenarios when a runtime exception is thrown because of incorrect overloading — I Doubt Any errors related to method overriding( — incase when the child class method has same name as Base class and same arguments as of base class —- )will be
• 
  Kraken
  polymorphism overriding method-overriding
  What is the difference between the two?A super class having myMethod(int a) and an inheriting class having the same method, Is this overriding or polymorphism?I am clear with the difference b/w overriding and overloading, but the polymorphism and overriding seems the same. Or are they?
• 
  omgzor
  java methods overriding
  Consider this:class A {int x =5; }class B extends A{int x =6;} public class CovariantTest {public A getObject() {return new A();}/*** @param args the command line arguments*/public static void main(String[] args) {// TODO code application logic hereCovariantTest c1 = new SubCovariantTest();System.out.println(c1.getObject().x);}}class SubCovariantTest extends CovariantTest {public B getObject(){return new B();} }As far as I know, the JVM chooses a method based on the true type of its object. Her
• 
  user732274
  objective-c overriding super
  I have a class A and a class B which is a subclass of A. Both have the following methods:-(void)anotherMethod{// implementation of A or B }-(void)aMethod{@try{[super aMethod];}@catch(NSException *e){}[self anotherMethod]; }Now: if I call [instanceOfClassB aMethod] the instruction [self anotherMethod] contained in A’s implementation of aMethod calls B’s anotherMethod (since it’s overridden) instead of A’s one. How can I make A’s implementation of aMethod call A’s implementation of anotherMethod?
• 
  uml
  java inheritance overriding
  This is the code in Java language:class A{A() { print(); }void print() { System.out.println(“A”); } } class B extends A{int i = Math.round(3.5f);public static void main(String[] args){A a = new B();a.print();}void print() { System.out.println(i); } }It prints 0, 4. But why does from the super class A within constructor you invoke subclass print method? I see that the print method is overridden, but in fact the ‘print’ method has been called from the superclass… That is the drill in order
• 
  mu is too short
  c++ subclassing overriding
  Normal overriding would work this way:class Fruit { public:string color(); };string Fruit::color() {return “Unkown”; };class Apple : public Fruit { public:string color(); };string Apple::color() {return “Green”; };Now, you’ld call this like:Apple *apple = new Apple(); std::cout << apple->color();This will output Green, which is correct! However, running it in the following situation (which is just an example, of course):Apple *apple = new Apple(); printHealthy(apple);// Method printHeal
• 
  Kon
  java overloading overriding
  Forgive me if this question is primarily opinion based, but I have the feeling that it is not and there is a good reason for the choice. So, here’s an example. Sorry, it’s really long, but super simple:Interface:public interface Shape {double area (); }Implementing class 1:import static java.lang.Math.PI;public class Circle implements Shape {private double radius;public Circle(double radius){this.radius = radius;}public double area(){return PI*radius*radius;} }Implementing class 2:public class
• 
  AlexDan
  c++ overriding
  why overriding is resolved at runtime whereas overloading is resolved at compile time ? is there any reason that overriding cant be resolved at compile time.
• 
  Alex Lockwood
  java android inheritance overriding
  Sometimes when I override methods, I get an exception the first time it’s called like below:05-31 21:32:04.266: E/AndroidRuntime(28471): android.support.v4.app.SuperNotCalledException: Fragment AnalFragment{41795860 #1 id=0x7f070002} did not call through to super.onDestroy()Why are we forced to call super.method()? It makes sense that there are obligations by the parent class, but more importantly, how do we know that a method requires super to be called, rather than waiting for it to crash?
• 
  LinuxPenseur
  c++ constructor overriding virtual-method
  Suppose I have two C++ classes:class A { public:A() { fn(); }virtual void fn() { _n = 1; }int getn() { return _n; }protected:int _n; };class B : public A { public:B() : A() {}virtual void fn() { _n = 2; } };If I write the following code:main() {B b;int n = b.getn(); }One might expect that n is set to 2.It turns out that n is set to 1. Why?
• 
  Lie Ryan
  java dynamic overloading overriding
  If I have a parent-child that defines some method .foo() like this: class Parent {public void foo(Parent arg) {System.out.println(“foo in Function”);} } class Child extends Parent {public void foo(Child arg) {System.out.println(“foo in ChildFunction”);} }When I called them like this:Child f = new Child();Parent g = f;f.foo(new Parent());f.foo(new Child()); g.foo(new Parent());g.foo(new Child());the output is:foo in Parent foo in Child foo in Parent foo in ParentBut, I want this output:foo in
• 
  skaffman
  android android-arrayadapter overriding
  While overriding ArrayAdapter to a custom adapter (FancyAdapter) I’ve got errors like Undefined getLayoutInflater(). Plus in constructor of custom adapter (FancyAdapter) class code super ( MainActivity.this, android.R.layout.simple_list_item_1, noteList ); getting error in “MainActivity.this” and “noteList” that they are inaccessible. My Code is as follow: —–MainActivity.java—–package my.android.notelist;import java.util.ArrayList;import android.app.Activity; import android.content.Context
• 
  Tom Sanders
  javascript overriding
  I’m having a spot of trouble overriding the document object for my JavaScript.function myFunction(document) {[code] }works fine. Butfunction myFunction(newDocument) {document=newDocument[code] }does not. So far I’m managing fine using functions with the former method, but I’d rather just override the document object once and forget about it. If anyone could show me the proper way to globally override the document object, I’d appreciate it.Thank you.
• 
  rchampourlier
  ruby-on-rails devise controllers overriding
  I’m trying to override a Devise controller to have some minor changes, for example adding a flash message when requesting a confirmation email for an unregistered email address.I tried to override Devise::ConfirmationsController1 this way:# app/controllers/confirmations_controller.rb class ConfirmationsController < Devise::ConfirmationsControllerinclude Devise::Controllers::InternalHelpers # tried to add this, no successdef createself.resource = resource_class.send_confirmation_instructions(p
• 
  mdb
  objective-c ios osx overriding
  ObjC has a very unique way of overriding methods. Specifically, that you can override functions in OSX’s own framework. Via “categories” or “Swizzling”. You can even override “buried” functions only used internally.Can someone provide me with an example where there was a good reason to do this? Something you would use in released commercial software and not just some hacked up tool for internal use?For example, maybe you wanted to improve on some built in method, or maybe there was a bug in a fr
• 
  Dmitry Beransky
  java api reflection overriding
  I’m making a kind of test program to be able to override methods in classes for an api I’m making in java but I’m getting a weird error when trying to invoke a method from another class…Here is the main “component class”:package st.cmp;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.HashMap;import java.util.List;public class Component {public class Overrider{Class<?> source;Class<?>[] overs;String name;p

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