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Questions tagged [extends]

extends is a keyword in several programming languages used to denote implementation inheritance

extends is a keyword in several programming languages which support object-oriented programming used to denote implementation inheritance (as opposed to implements used to denote interface inheritance).

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Interface extends another interface but implements its methods

In java when an interface extends another interface: Why does it implement its methods? How can it implement its methods when an interface can't contain a method body How can it implement the methods when it extends the other interface and not…
GingerHead
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Generics : List is same as List?

I am just trying to understand the extends keyword in Java Generics. List means we can stuff any object in the List which IS A Animal then won't the following also mean the same thing: List Can someone help me know the…
peakit
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Why "extends" precedes "implements" in class declaration

Why must implement always be written after extend in a class declaration? For example: public class Register extends ActionSupport implements ModelDriven Why can it not be: public class Register implements ModelDriven extends ActionSupport The…
lzjun
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Java why interface extends interface

I am wondering under what circumstances do we extend an interface from an interface? Because, for example interface A{ public void method1(); } interface B extends A{ public void method2(); } class C implements B{ @Override public void…
peter
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extends and implements in one class in TypeScript

Can I do this in TypeScript? export interface IMyInterface { doSomething(): void; } export class MyBaseClass { myBaseClassHasProperty: string; constructor(){ this.myBaseClassHasProperty = 'some value'; } myBaseClassHasMethods(): void…
Everton Santos
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PHP - extended __construct

I was wondering if you could help me out.. I have two classes, one extends the other.. Class B will be extended by various different objects and used for common database interactions.. Now I would like class B to handle its connect and disconnects…
Lee
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how to extend service with dependencies in angular 2

I have a parent service which has some dependencies like @Injectable() export class ParentService{ constructor(private http:Http, private customService:CustomService){} } and I want to extend the service @Injectable() export class ChildService…
Han Che
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How to merge objects?

For instance, from these two objects : var object1 = { "color": "yellow", "size": null, "age": 7, "weight": null } var object2 = { "color": "blue", "size": 51, "age": null } I want this (object2 overrides object1 except for null…
TrtG
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extends class and implements interface in java

interface Bouncable{ } interface Colorable extends Bouncable{ } class Super implements Colorable{ } class Sub extends Super implements Colorable {} // Ok (case -1) But, class Sub implements Colorable extends Super {} // error (case -2) Why…
Ravi
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PHPUnit 6.1.x throws array_merge() error when my test class uses its own constructor method

I get this error: 1) XTest::testX array_merge(): Argument #1 is not an array ERRORS! Tests: 1, Assertions: 0, Errors: 1. On this test case: use PHPUnit\Framework\TestCase; class XTest extends TestCase { function __construct() {} …
Dennis
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Extending Protobuf Messages

I have many different schemas, however there are a set of fields which every schema contains. I was wondering if there was a way to have a different schema extend a parent schema and inherit its fields. For example this is what I want: message…
user1413793
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C++ equivalent of using for a java parameter/return type

In java, to make a function that returns an object that is the same type as a parameter and extends a certain class, I would type: public T foo(T bar) {...} Is there a C++ equivalent of this? In other words, how do I make a…
ricky3350
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Hibernate @Embeddable class which extends another @Embeddable class, Properties not found for @OneToMany mapping

We are translating old xml based configuration to Annotation based configuration Situation There is a class which is annotated as @Embeddable(ParentPk.java), another class extends this class which is @Embeddable(ChildPk.java), this ChildPk.java is…
Yahya Arshad
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Typescript Inheritance: Expanding base class object property

When extending a class, I can easily add some new properties to it. But what if, when I extend a base class, I want to add new properties to an object (a property which is a simple object) of the base class? Here is an example with some code. base…
Clorofilla
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What's the difference between the implements & extends keywords in Java

What's the difference between the following keywords in Java: implements, extends?
sachin
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