What is aggregation and composition in Java with examples?

Asked By: Vidala Zhikov | Last Updated: 2nd February, 2020
Category: technology and computing programming languages
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Dependency: Aggregation implies a relationship where the child can exist independently of the parent. For example, Bank and Employee, delete the Bank and the Employee still exist. whereas Composition implies a relationship where the child cannot exist independent of the parent.

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Herein, what is aggregation and composition?

In both aggregation and composition object of one class "owns" object of another class. But there is a subtle difference: Aggregation implies a relationship where the child can exist independently of the parent. Composition implies a relationship where the child cannot exist independent of the parent.

Secondly, what is composition in object oriented programming? Composition is one of the fundamental concepts in object-oriented programming. It describes a class that references one or more objects of other classes in instance variables. This allows you to model a has-a association between objects. You can find such relationships quite regularly in the real world.

Also asked, what is aggregation explain with example?

Aggregation is a way of composing different abstractions together in defining a class. For example, a car class can be defined to contain other classes such as engine class, seat class, wheels class etc. Other examples of aggregation are: A window class containing menu class, check-box class etc.

What is segregation and aggregation in Java?

Aggregation is having a bunch of objects in another object. For example, you aggregate a bunch of items in an ArrayList. Segregation typically deals with separation of concerns. For example, you segregate presentation from the view in MVC.

39 Related Question Answers Found

What is composition and example?

The definition of composition is the act of putting something together, or the combination of elements or qualities. An example of a composition is a flower arrangement. An example of a composition is a manuscript. An example of a composition is how the flowers and vase are arranged in Van Gogh's painting Sunflowers.

What are different types of aggregation?

Association, Aggregation, Composition, Abstraction, Generalization, Realization, Dependency
  • Association. Association is a relationship between two objects.
  • Aggregation. Aggregation is a special case of association.
  • Composition. Composition is a special case of aggregation.
  • Generalization.
  • Realization.
  • Dependency.

What is an interface?

In computing, an interface is a shared boundary across which two or more separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these.

What is difference between inheritance and composition?

Though both Inheritance and Composition provides code reusablility, main difference between Composition and Inheritance in Java is that Composition allows reuse of code without extending it but for Inheritance you must extend the class for any reuse of code or functionality.

What is difference between association aggregation and composition?

The composition is stronger than Aggregation. In Short, a relationship between two objects is referred as an association, and an association is known as composition when one object owns other while an association is known as aggregation when one object uses another object.

Is a relationship in OOP?

One of the advantages of Object-Oriented programming language is code reuse. Object oriented programming generally support 4 types of relationships that are: inheritance , association, composition and aggregation. All these relationship is based on "is a" relationship, "has-a" relationship and "part-of" relationship.

What is aggregation class diagram?

An aggregation is a special type of association in which objects are assembled or configured together to create a more complex object. For example, a Department class can have an aggregation relationship with a Company class, which indicates that the department is part of the company.

Is a relationship in C++?

Wherever you see an extends keyword or implements keyword in a class declaration, then this class is said to have IS-A relationship. HAS-A Relationship: Composition(HAS-A) simply mean the use of instance variables that are references to other objects.

What is another word for aggregation?

collection, aggregation, accumulation, assemblage(noun) several things grouped together or considered as a whole. Synonyms: accruement, gathering, collecting, accretion, assembly, assemblage, ingathering, assembling, collection, appeal, accrual, hookup, accumulation, solicitation, compendium.

What is aggregation in biology?

Protein aggregation is a biological phenomenon in which mis-folded proteins aggregate (i.e., accumulate and clump together) either intra- or extracellularly. These protein aggregates are often correlated with diseases.

What is polymorphism in OOP?

In object-oriented programming, polymorphism refers to a programming language's ability to process objects differently depending on their data type or class. More specifically, it is the ability to redefine methods for derived classes.

What do you mean by aggregation?

An aggregation is a collection, or the gathering of things together. Your baseball card collection might represent the aggregation of lots of different types of cards. Aggregation comes from the Latin ad, meaning to, and gregare, meaning herd. So the word was first used to literally mean to herd or to flock.

What is difference between inheritance and aggregation?

Inheritance: extend the functionality of a class by creating a subclass. Override superclass members in the subclasses to provide new functionality. Aggregation: create new functionality by taking other classes and combining them into a new class.

Is an aggregation process?

Aggregation is the process of combining things. That is, putting those things together so that we can refer to them collectively.

What is Association and its types?

An association type (also called an association) is the fundamental building block for describing relationships in the Entity Data Model (EDM). In a conceptual model, an association represents a relationship between two entity types (such as Customer and Order ).

What is the purpose of an aggregator?

A content aggregator is an individual or organization that gathers Web content (and/or sometimes applications) from different online sources for reuse or resale. ScreamingMedia, Moreover, and iSyndicate are among the increasing number of companies offering aggregated content for resale.

What is Polymorphism in Java?

Polymorphism in Java is a concept by which we can perform a single action in different ways. We can perform polymorphism in java by method overloading and method overriding. If you overload a static method in Java, it is the example of compile time polymorphism. Here, we will focus on runtime polymorphism in java.