I want to create a common service and common request as shown below: Then implement this service as shown below: However, although CompanyARequest is inherited from CommonRequest, createOrUpdate method throws “Method does not override method from its superclass” error. On the other hand, if I use …
Tag: interface
How can I implement interface correctly?
I am doing homework of making a simple calculator using java and interface in java. but the class that implements java gives error saying here is the code Answer There are a couple of issues here. First, since BasicCalculator is a public class, it needs to be defined in its own file named BasicCalculator.java…
Can you change the Type of Java Exception’s error message?
I’m writing an Internal-Facing tool with a very slow runtime. Because of this runtime I’m trying to validate the input for errors and send a JSON object with a detailed list of every missing or failing element to the client before actually running the tool. I was wondering if there was a way to mo…
Trying to mimic java functional interface
I am trying to mimic the java’s Function<T,R> by writing below code : when I am writing below code in andThen, it’s working fine (pointing to apply(T t) of interface) and perfectly chaining the other functional implementations But when writing below snippet, it’s falling into recursion…
What’s the meaning of this line of code? And how can I create an object of this class?
I was trying to construct an object of the MTree class (https://github.com/Waikato/moa/blob/master/moa/src/main/java/moa/clusterers/outliers/utils/mtree/MTree.java) The constructor of MTree looks like this: The DistanceFunction here is an interface, the code of it is: And it’s implementation is: And my …
How to implement a generic interface that extends another generic interface in Java?
I am new to Java and working on implementing generic interfaces and that’s where I’d love some help. I want to implement a generic interface in Java that extends another interface. This is how the current interface structure looks like – I want to implement the ItemsProviderInterface interfa…
Creating new instance of concrete implementation in interface – is this an antipattern?
Let’s say I have the interface AuthorDao with two different implementation classes for example MyAuthorDaoImpl1 and MyAuthorDaoImpl2. In my interface AuthorDao I have some basic crud methods and one extra method which is static for getting a new instance of MyAuthorDaoImpl1. It looks like this: Question…
Implementing List interface for CustomList in Java
I need to create a custom list that adds elements in pairs. I copied a similar implementation and adjusted it as needed, but unfortunately, it doesn’t work. And I have this for testing my code so far. The problem is that when I call add method the size of the list increases by 2 as it should, but nothin…
Define Methods in Interface Without Specifying Number of Parameters
I’m trying to implement classes from the same interface but with a different number of parameters in method like the code below. Is there a way in Java to define methods in the interface without constraining the number of parameters? Answer You could use the ellipsis syntax (…) and then check the …
How can I make classes implement an interface and print their methods based on a given parameter in Java?
I think this might be a very basic Java question, and I apologize since I’m a beginner, but I want to understand what am I getting wrong here: I’m supposed to create a package, and inside it, I must create the following: an interface with a method (the question says nothing besides it, so I create…