Base obj=new Child(); What are the advantage and real life application of above code?

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Have you ever observed while communicating with databases? You can find such type of example while writing code from communicating with DB. Connection connectionObject = DriverManager.getConnection(); or Statement simpleStatement = connectionObject.getStatement(); The value of the connectionObject...
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Have you ever observed while communicating with databases? You can find such type of example while writing code from communicating with DB. Connection connectionObject = DriverManager.getConnection(); or Statement simpleStatement = connectionObject.getStatement(); The value of the connectionObject variable depends on the database driver you are using (most of the time you load the driver with Class.forName("some driver implementaion")). The answer for your question is, such type of coding helps you to implement and use your own mechanism that suits to your requirements / circumstances. read less
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You can get all the attributes and behavior of a class by creating its object.
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Dynamic Polymorphism which promotes calling only those methods which parent is aware of. Mostly used in API creation.
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1.It is basis of Polymorphism. 2. Lets say you have a parent class called Animal and child classes called Dog, Cat, and Lizard. Each class has a method call makeSound(). Then when you say Animal a1 = new Dog(); and Animal a2 = new Cat(), a1.makeSound() will bark and a2.makeSound() will meow. The...
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1.It is basis of Polymorphism. 2. Lets say you have a parent class called Animal and child classes called Dog, Cat, and Lizard. Each class has a method call makeSound(). Then when you say Animal a1 = new Dog(); and Animal a2 = new Cat(), a1.makeSound() will bark and a2.makeSound() will meow. The technical term for this behavior is called polymorphism. It is useful for code reuse. You only need to write code once for an application that has Animals makeSound() when they are happy, instead of separate code for each animal type. 3.Another use of polymorphism is hiding your code's implementation from other users. For example you can show other users that you are using a List and then you have the choice to implement the List as a LinkedList or as an ArrayList. You can also choose a LinkedList and then at a later time switch to an ArrayList without effecting your users. You also can't say Dog d = new Animal() because a Dog is an Animal but an Animal is not necessarily a Dog. read less
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This is the most fundamental use of polymorphism because using a parent class reference to refer to a child object is what allows you to take advantage of the benefits of polymorphism. Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs...
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This is the most fundamental use of polymorphism because using a parent class reference to refer to a child object is what allows you to take advantage of the benefits of polymorphism. Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object. read less
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Advantage of method overriding in JAVA The main advantage of method overriding is that the class can give its own specific implementation to a inherited method without even modifying the parent class in JAVA Dynamic method dispatch is a technique which enables us to assign the base class reference...
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Advantage of method overriding in JAVA The main advantage of method overriding is that the class can give its own specific implementation to a inherited method without even modifying the parent class in JAVA Dynamic method dispatch is a technique which enables us to assign the base class reference to a child class object. As we see in the code sample that the base class reference is assigned to child class object in JAVA. Base obj=new Child(); read less
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This is the basis for polymorphism: Imagine you have several child classes that inherit from you parent class. You want to use all these child classes through the interface / methods defined on your parent class, without worrying about the implementation details in each child class (each might do something...
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This is the basis for polymorphism: Imagine you have several child classes that inherit from you parent class. You want to use all these child classes through the interface / methods defined on your parent class, without worrying about the implementation details in each child class (each might do something different, but with the same overall semantics). This is possible because the child class has a IS A relationship with its parent class since child inherits from parent. read less
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And the source code that follows can be common regardless of whether 'a' is Cat or Dog
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Animal a = new Cat(); String s = a.getScientificName(); In the above code, the call to getScientificName() can be used regardless of whether the variable 'a' references a Cat object or a Dog object. So, Base obj = new Chlld(); obj.commonMethod(); // allows using common source code regardless...
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Animal a = new Cat(); String s = a.getScientificName(); In the above code, the call to getScientificName() can be used regardless of whether the variable 'a' references a Cat object or a Dog object. So, Base obj = new Chlld(); obj.commonMethod(); // allows using common source code regardless of the Child object being referenced by obj. read less
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The child class which extends an abstract base class must implement all the abstract methods that are provided in the abstract base class. And the most important point with the abstract classes is that you cannot instantiate them.
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