When a class implements several interfaces that define different constructors, the class would have to implement several constructors, each one satisfying only one interface, but not the others. It will be impossible to construct an object that calls each of these constructors.

Jan 28, 2021 · Generic Interfaces in Java are the interfaces that deal with abstract data types. Interface help in the independent manipulation of java collections from representation details. They are used to achieving multiple inheritance in java …

Apr 18, 2019 · I have written an interface and now need to write a constructor in the AlertService class, that accepts this interface (AlertDAO). I don't really understand the concept. Can anyone explain?

No, you cannot have a constructor within an interface in Java. You can have only public, static, final variables and, public, abstract, methods as of Java7. From Java8 onwards interfaces allow default methods and static methods. From Java9 onwards interfaces allow …

In Java, constructors can be divided into three types: 1. Java No-Arg Constructors. Similar to methods, a Java constructor may or may not have any parameters (arguments). If a constructor does not accept any parameters, it is known as a no-argument constructor. For example, // body of the constructor . int i;

Aug 29, 2021 · Prerequisite: Interface and Abstract class in Java. A Constructor is a special member function used to initialize the newly created object. It is automatically called when an object of a class is created. Why interfaces can not have the constructor? An Interface is a complete abstraction of class.

Mar 28, 2025 · An Interface in Java programming language is defined as an abstract type used to specify the behaviour of a class. An interface in Java is a blueprint of a behaviour. A Java interface contains static constants and abstract methods. Key Properties of Interface:

Another way to achieve abstraction in Java, is with interfaces. An interface is a completely " abstract class " that is used to group related methods with empty bodies: To access the interface methods, the interface must be "implemented" (kinda like inherited) by another class with the implements keyword (instead of extends).

Sep 11, 2022 · In order to call any method we need an object since there is no need to have object of interface, there is no need of having constructor in interface (Constructor is being called during creation of object).

Mar 22, 2025 · Interfaces cannot have constructors because they are not designed to be instantiated directly. Their primary role is to define a contract, not to hold state or provide instantiation logic. Why...