Inheritance refers to using the structure and behavior of a superclass in a subclass. Polymorphism refers to changing the behavior of a superclass in the subclass.v

Inheritance is more a static thing (one class extends another) while polymorphism is a dynamic/ runtime thing (an object behaves according to its dynamic/ runtime type not to its static/ declaration type).

Inheritance is when a ‘class’ derives from an existing ‘class’. So if you have a Person class, then you have a Student class that extends Person, Student inherits all the things that Person has.

Polymorphism deals with how the program decides which methods it should use, depending on what type of thing it has. If you have a Person, which has a read method, and you have a Student which extends Person, which has its own implementation of read, which method gets called is determined for you by the runtime, depending if you have a Person or a Student

Person p = new Student();
p.read();

The read method on Student gets called. Thats the polymorphism in action. You can do that assignment because a Student is a Person, but the runtime is smart enough to know that the actual type of p is Student.

The main difference is polymorphism is a specific result of inheritance. Polymorphism is where the method to be invoked is determined at runtime based on the type of the object. This is a situation that results when you have one class inheriting from another and overriding a particular method. However, in a normal inheritance tree, you don’t have to override any methods and therefore not all method calls have to be polymorphic