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    What is Aggregation and how it maps into a Java class?

    An Aggregation is an Association which denotes an "is part of" relationship.

    Take a 'Car', for example, it is consisted of an engine,a steering wheel, four tires,seats,gear box,fuel tank,engine oil tank, air filters etc.So all constituents of car are parts of it.

    If a car is destroyed/smashed, its parts can still be used separately as spares in other cars,so these parts have individual use even when their conatiner entity is destroyed.

    In a Java class, an aggregation can be represented from above example as :

    class Car
    List getTires();
    List getSeats();
    List getAllParts();


    1. Inheritence means --> "is-a" relationship
      e.g. HONDA CITY is-a CAR

      Aggregation means --> "has-a" relationship
      HONDA CITY has-a engine

      Hope this makes it clear !!!

    2. Thanks Vinay for clearance ... take care buddy !!


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