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Compile-Time Polymorphism in Java

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Compile-Time Polymorphism in Java

Polymorphism — one name, many forms. Compile-time: overloading.

Runtime — parent reference, child object, overridden method.

Interview line — Animal a = new Cat(); a.sound(); → Meow.

Write one tiny example for Compile-Time Polymorphism. Compile, print one result, and say the output out loud before you type.

Use Compile-Time Polymorphism only when the problem needs it. Don’t force it into every program. Know one beginner trap.

Let's take this on the board with one tiny Main class — no extra files. Compile-Time Polymorphism in Java — output: Meow. a looks like Animal, but the real object is Cat — runtime polymorphism. Start from main, go line by line, and stop at each print. That output is the proof for Compile-Time Polymorphism.

Exam tip

Write Animal a = new Cat(); then say which sound() runs.

Example

class Animal {
  void sound() { System.out.println("Some sound"); }
}
class Cat extends Animal {
  @Override
  void sound() { System.out.println("Meow"); }
}
public class Main {
  public static void main(String[] args) {
    Animal a = new Cat();
    a.sound();
  }
}

Compile-Time Polymorphism in Java — output: Meow. a looks like Animal, but the real object is Cat — runtime polymorphism.

Short notes

DefCompile-Time Polymorphism is a Java idea you should explain with one small example.
RuleKnow the keyword / API used for Compile-Time Polymorphism. Type a tiny Main and print one result.
RememberFor Compile-Time Polymorphism, say the output before you code.
TrapCompile-Time Polymorphism — only memorising the heading. No example, no trap.
One name, many forms
Overload = compile time

class Animal { void sound() { System.out.println("Some sound"); } } class Cat extends Animal { @Override void sound() { System.out.println("Meow"); } } public class Main { public static void main(String[] args) { Animal a = new Cat(); a.sound(); } }

Compile-Time Polymorphism in Java

Example

Short notes

Questions

Compile-Time Polymorphism in Java

Example

Short notes

Questions