How does the instanceof operator work in the context of downcasting in java?
I am trying to understand the purpose of using the instanceof operator as a way to properly downcast an object.
public class Test {
public static void main(String args) {
Dog k = new Dog();
Animal v = new Dog();
if (v instanceof Dog){
k = (Dog)v;
k.getAnimalName(); // displays Parent Animal
k.getDogName(); // displays Dog
}
}
public class Dog extends Animal{
public void getDogName(){
System.out.println("Dog");
}
}
public class Animal{
public void getAnimalName(){
System.out.println("Parent Animal");
}
}
Confused about how v is an instance of type Dog. Can someone please explain this?
Confused about what was displayed in the method calls (referring to k.getAnimalName() and k.getDogName). Is the reason behind why k could call both methods is because the type of k is a subclass of Animal?
java casting downcasting
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
add a comment |
I am trying to understand the purpose of using the instanceof operator as a way to properly downcast an object.
public class Test {
public static void main(String args) {
Dog k = new Dog();
Animal v = new Dog();
if (v instanceof Dog){
k = (Dog)v;
k.getAnimalName(); // displays Parent Animal
k.getDogName(); // displays Dog
}
}
public class Dog extends Animal{
public void getDogName(){
System.out.println("Dog");
}
}
public class Animal{
public void getAnimalName(){
System.out.println("Parent Animal");
}
}
Confused about how v is an instance of type Dog. Can someone please explain this?
Confused about what was displayed in the method calls (referring to k.getAnimalName() and k.getDogName). Is the reason behind why k could call both methods is because the type of k is a subclass of Animal?
java casting downcasting
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
What doesextendsmean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.
– Joakim Danielson
Dec 30 '18 at 16:16
add a comment |
I am trying to understand the purpose of using the instanceof operator as a way to properly downcast an object.
public class Test {
public static void main(String args) {
Dog k = new Dog();
Animal v = new Dog();
if (v instanceof Dog){
k = (Dog)v;
k.getAnimalName(); // displays Parent Animal
k.getDogName(); // displays Dog
}
}
public class Dog extends Animal{
public void getDogName(){
System.out.println("Dog");
}
}
public class Animal{
public void getAnimalName(){
System.out.println("Parent Animal");
}
}
Confused about how v is an instance of type Dog. Can someone please explain this?
Confused about what was displayed in the method calls (referring to k.getAnimalName() and k.getDogName). Is the reason behind why k could call both methods is because the type of k is a subclass of Animal?
java casting downcasting
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
I am trying to understand the purpose of using the instanceof operator as a way to properly downcast an object.
public class Test {
public static void main(String args) {
Dog k = new Dog();
Animal v = new Dog();
if (v instanceof Dog){
k = (Dog)v;
k.getAnimalName(); // displays Parent Animal
k.getDogName(); // displays Dog
}
}
public class Dog extends Animal{
public void getDogName(){
System.out.println("Dog");
}
}
public class Animal{
public void getAnimalName(){
System.out.println("Parent Animal");
}
}
Confused about how v is an instance of type Dog. Can someone please explain this?
Confused about what was displayed in the method calls (referring to k.getAnimalName() and k.getDogName). Is the reason behind why k could call both methods is because the type of k is a subclass of Animal?
java casting downcasting
java casting downcasting
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
edited Dec 30 '18 at 15:56
Olive Town
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
asked Dec 30 '18 at 3:55
Olive TownOlive Town
53
53
What doesextendsmean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.
– Joakim Danielson
Dec 30 '18 at 16:16
add a comment |
What doesextendsmean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.
– Joakim Danielson
Dec 30 '18 at 16:16
What does
extends mean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.– Joakim Danielson
Dec 30 '18 at 16:16
What does
extends mean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.– Joakim Danielson
Dec 30 '18 at 16:16
add a comment |
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What does
extendsmean? Do you understand the concept of inheritance in object-oriented programming? I think you need to do some basic research.– Joakim Danielson
Dec 30 '18 at 16:16