Compile time polymorphism

Question

I have a question about compile time polymorphism in java.

Is method overloading a way to achieve compile time polymorphism? If it is, is it the only way? Little example would help me a lot.

I searched in the web and different sources give different answers and its confusing. That is why I thought of asking it here.

Thanks in advance.

Answer 1

I found this external source. It makes the statement that there is no "compile time polymorphism". You probably mean "runtime polymorphism"?

Essentially, polymorphism refers to the feature that a method is not executed by a fixed method implementation that is defined at compile time, but rather there is a lookup at runtime which method implementation is chosen to execute the call.

For example, there is Object::equals in Java, which has an implementation in the "Object" class. If you create you own class that has its own implementation of the "equals" method, that implementation will be chosen when you compare instances, instead of the implementation defined in the "Object" class.

Polymorphism gets really handy when the complete list of implementations for a method is unknown, e.g. because you provide a library that is used in programs/other libraries that can declare their own (derived) classes that implement the method.