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 …

Is it possible to make a generic functional interface with optional parameter(s)?

I’m trying to create a functional interface in Java with a single method (of course) that can take any type of parameter(s) and return any data type (i.e. a generic method). This is what I have so far:…

How can I create a stream of objects?

Let’s say I have: interface SomeInterface { Foo getFoo(); } and class SomeClass implements SomeInterface { Foo getFoo() { //returns a Foo object } } Then in a service, I …

How to present abstract class which has relationship with interface class in class diagram

I have to do diagram with minimum of one abstract class and interface.I though to be a good idea to implement the interface class here. My table is customer which is the abstract class.The interface …

access interface out of the class java

I have a class A, another is B, there is one interface Ai with one method ok() only. Class A implements Ai, inside the ok I’m printing just a line. Class B has an instance of A, I want to access A’s …

What is the purpose of a static method in interface from Java 8?

Why are static methods supported from Java 8? What is the difference between the two lines in main method in below code? package sample; public class A { public static void doSomething() { …