Skip to main content

inheritance in java



  • Inheritance allows a software developer to derive a new class from an existing one
  • The existing class is called the parent class, or super class, or base class
  • The derived class is called the child class or subclass.
  • As the name implies, the child inherits characteristics of the parent
  • That is, the child class inherits the methods and data defined for the parent class
  • To tailor a derived class, the programmer can add new variables or methods, or can modify the inherited ones
  • Software reuse is at the heart of inheritance
  • By using existing software components to create new ones, we capitalize on all the effort that went into the design, implementation, and testing of the existing software
  • Inheritance relationships often are shown graphically in a UML class diagram, with an arrow with an open arrowhead pointing to the parent class




Examples 
ex 1 

ex 2


Comments

Post a Comment

Popular posts from this blog

Generalization and Specialization

Generalization creates a concept with a broader scope. Specialization creates a concept with a narrower scope. Reusing the interface!  Inheritance: get the interface from the general class. Objects related by inheritance are all of the same type.

The Class Concept

A class is a collection of objects (or values) and a corresponding set of methods.  A class encapsulates the data representation and makes data access possible at a higher level of abstraction. Example 1: A set of vehicles with operations for starting, stopping, driving, get km/liter, etc. Example 2: A time interval, start time, end time, duration, overlapping intervals, etc. Example 3: A string, upper case, compare, lower case, etc.  str.equals(otherStr) – class/Java style   strcmp(str, otherStr) – C style

The Object Concept

An object is an encapsulation of data.  An object has identity (a unique reference)  social security number (cpr), employee number, passport number state, also called characteristics (variables)  hungry, sad, drunk, running, alive  behavior (methods) eat, drink, wave, smile, kiss  An object is an instance of an class   A class is often called an Abstract Data Type (ADT).