Feature: Added a java doc link for optional.

Author: syedumerahmedcode

README.md

@@ -193,6 +193,7 @@ Similarly, a BiFunction _incrementByOneAndMultiplyBiFunction_ is also created wh
 - [7](https://codeburst.io/declarative-vs-imperative-programming-a8a7c93d9ad2): Declarative vs Imperative Programming
 - [8](https://mkyong.com/tutorials/java-8-tutorials/): Java 8 Tutorials(From Mkyong)
 - [9](https://stackoverflow.com/questions/8736378/what-is-a-callback-in-java): What is a callback function?
+- [10](https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html): Optional **(JavaDoc)**
 
 
 

notes.md

@@ -4,8 +4,6 @@
      
 Some methods used in the project:
 
-- **Function<T,R>**: Represents a function that accepts one argument and produces a result.
-- **BiFunction<T,U,R>**: Represents a function that accepts two arguments and produces a result.
 
 
 - **Predicate<T>**: Represents a predicate(boolean-valued function) of one argument.