1.Function: To transform arguments in returnable value.

2.Predicate: To perform a test and return a Boolean value.

3.Consumer: Accept arguments but do not return any values.

4.Supplier: Do not accept any arguments but return a value. 

 A Stream can process the following data:

• A collection of an Array.
• An I/O channel or an input device.
• A reactive source (e.g., comments in social media or tweets/re-tweets) 
• A stream generator function or a static factory

 Method reference is a compact way of referring to a method of functional interface. It is used to refer to a method without invoking it. :: (double colon) is used for describing the method reference. The syntax is class::methodName

 Python Graphics Trick

Source Code:-