Overriding an abstract method means class abstract class or not in java?

» java » Overriding an abstract method means class abstract class or not in java?

By : Mithun Sharma

Date : November 28 2020, 01:01 AM

fixed the issue. Will look into that further If you extend A and implement the abstract method (as you have done), B does not have to be abstract.
On a related note, if you only have one abstract method and no concrete methods, you could declare your abstract class instead as an interface like so:

code :

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Java Overriding abstract class method with an interface as param

By : user3172178

Date : March 29 2020, 07:55 AM

around this issue Your class Bar doesn't override insert, because the parameter types must match exactly. This is because your implementation takes an InterfaceImplementation, not a SomeInterface.
What you can do to get this to compile:

code :

public abstract class Foo<T extends SomeInterface>{

public abstract boolean insert(T param);

public class Bar extends Foo<InterfaceImplementation>{

@Override
public boolean insert(InterfaceImplementation param){

method adding objects extending abstract class to Arraylist of type Abstract Class in java

By : ani

Date : March 29 2020, 07:55 AM

fixed the issue. Will look into that further In order to use the 'T' as a generic type, you need to indicate this at the class declaration. Then within properties and methods on your class Anthill, you can then reference it throughout:

code :

public class Anthill<T extends Ant_Abstract>{
     public ArrayList<T> occupants = new ArrayList<>(15);

     public void enter(T ant){
            occupants.add(ant);
     }
}

     public ArrayList<T> occupants = new ArrayList<>(15);

Overriding equals method by a abstract class and set it as abstract so if any class extends, they must implement

By : David waless

Date : March 29 2020, 07:55 AM

may help you . First off, interfaces do not override methods. So you cannot override equals from Object by adding an equals method to an interface. Interfaces instead can be thought of as contracts, they guarantee that any non-abstract class implementing them will have all of the interfaces methods (either directly or through inheritance).
In regards to making a method abstract through inheritance, you can in fact do this. So your example of overriding the equals method with an abstract definition in your abstract Box class will cause any classes extending Box to have to implement an equals method.

Best practice in Java for extending abstract class with overriding one method

By : ISEVA

Date : March 29 2020, 07:55 AM

With these it helps I would move all common methods in A1 to another level of abstraction (let's call it ABase), and declare in A1 and A2 their special behaviors (if any).
This way if more classes of the same type as C3 are added they don't need to redefine again methodA.

code :

public interface I1 {
  public void methodA();
}

public abstract class ABase implements I1 {
  //other methods
}

public abstract class A1 extends ABase {
  public void methodA(){
    //default behaviour
  }
}

public abstract class A2 extends ABase {
  public void methodA(){
    //default behaviour
  }
}

public class C1 extends A1 {
  //do nothing regarding methodA, because the default behaviour in A1 is desired
  //other methods
}

public class C2 extends A1 {
  //do nothing regarding methodA, because the default behaviour in A1 is desired
  //other methods
}

public class C3 extends A2 {
  //do nothing regarding methodA, because the default behaviour in A2 is desired
  //other methods
}

Java Abstract Class with Abstract Method with Abstract Class-Parameter

By : Randy

Date : March 29 2020, 07:55 AM

With these it helps CClass1 must implement a method which can take any AClass2 as you have specificed that it would. You can overload this method, but you have to implement the abstract methods of the parent.