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mjstx

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JCHJava Community | Help. Code. Learn.

•Created by mjstx on 1/2/2025 in #java-help

Java GUI not loading images/ImageIcons help

9 replies

JCHJava Community | Help. Code. Learn.

•Created by mjstx on 12/10/2024 in #java-help

java basics help

For this example:

public class Animal {
public void makeSound (){
   System.out.println("animal sounds");
   }
 }

public class Cat extends Animal{
public void makeSound (){
   System.out.println("meow");
   }
 }

public class Dog extends Animal{
public void makeSound (){
   System.out.println("woof");
   }
 }

public class test {
Animal dog = new Dog();
Animal cat = new Cat();
}

public class Animal {
public void makeSound (){
   System.out.println("animal sounds");
   }
 }

public class Cat extends Animal{
public void makeSound (){
   System.out.println("meow");
   }
 }

public class Dog extends Animal{
public void makeSound (){
   System.out.println("woof");
   }
 }

public class test {
Animal dog = new Dog();
Animal cat = new Cat();
}

I dont understand why we do this: Animal dog = new Dog(); Animal cat = new Cat(); Why not just do something like, Dog dog = new Dog();, Cat cat = new Cat(); Also why CAN we do this and why doesnt it throw an error, because ive seen it happen that the left hand side of the initialization was sometimes an interface? One thing that I found online was thit helps with abstraction, like for the method below. But why does it even make a difference at all, since Dog dog = new Dog(); is still an Animal so the method should it accept it too right? public void handleSound (Animal animal) { animal.makeSound(); }

39 replies

JCHJava Community | Help. Code. Learn.

•Created by mjstx on 6/5/2023 in #java-help

Creating a Java Unit test vectoraddition

17 replies

JCHJava Community | Help. Code. Learn.

•Created by mjstx on 6/4/2023 in #java-help

Junit test calling upon variable from a different class's method

19 replies

JCHJava Community | Help. Code. Learn.

•Created by mjstx on 6/4/2023 in #java-help

JUnit Test confusion

71 replies

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