Have to throw out that disclosure ð. While there are a number of essential oils you can use for minor migraines and head pain, two of the top single oils are Peppermint and Lavender. Peppermint is effective for helping to relieve minor symptoms of those mind-numbing headaches that come from a variety of culprits.
An abstract class is like a class, but differs in that it only defines generic methods in the class, but does not actually implement them. Those methods will be implemented later by specialized sub-classes. This is how we get interfaces - interfaces are the implementation of the abstract class.
Once an interface has been implemented by a class, a client can create an object from the class and communicate with it through an interface reference. You can use an interface to create an object reference but not the object itself. This makes sense because an object requires data properties and method implementations that cannot be supplied by an interface. Because it is not a creatable entity, an interface is an abstract data type.