Learn Functional Programming with Java using a Hands-on Step by Step Approach
Wanna start playing with Functional Programming? Want to write awesome Java code with Functional Programming using Streams, Lambda Expressions, Functional Interfaces and Method References? Want to make your Java Programs more performant and parallelizable using Functional Programming?
Functional Programming is an essential skill for Java Programmers today.
Are you ready to learn about Functional Programming and take the next step in your programming career?
Do you want to join 300,000+ learners having Amazing Learning Experiences with in28Minutes?
Look No Further!
Functional Programming was introduced into Java in Java 8. Additional Functional Programming Enhancements were introduced in Java 9.
In this handson course, we will learn to write awesome Java code with Functional Programming. You will learn the basics of Functional Programming - Lambda Expressions, Method References, Streams and Functional Interfaces.
This course would be a perfect first step as an introduction to Functional Programming.
You will be using using Eclipse (Java IDE) and Java 9 in this course. We will help you set up each one of these.
System.out.println("Ranga")
List<Integer> numbers = List.of(12, 9, 13, 4, 6, 2, 4, 12, 15);
numbers.stream().reduce(0, (x,y)->x+y)
numbers.stream().reduce(0, (x,y)->x)
numbers.stream().reduce(0, (x,y)->y)
numbers.stream().reduce(0, (x,y)-> x>y ? x:y)
numbers.stream().reduce(Integer.MIN_VALUE, (x,y)-> x>y ? x:y)
numbers.stream().reduce(Integer.MIN_VALUE, (x,y)-> x>y ? y:x)
numbers.stream().reduce(Integer.MAX_VALUE, (x,y)-> x>y ? y:x)
numbers
numbers
numbers.stream().reduce(0, (x,y) -> x*x + y*y)
numbers.stream().map(x -> x*x).reduce(0, Integer::sum)
numbers.stream().map(x -> x*x*x).reduce(0, Integer::sum)
numbers.stream().filter(x -> x%2==1).reduce(0, Integer::sum)
numbers.stream().filter(x -> x%2==0).reduce(0, Integer::sum)
numbers.stream().distinct().forEach(System.out::println)
numbers
numbers.stream().sorted().forEach(System.out::println)
numbers.stream().distinct().sorted().forEach(System.out::println)
List<String> courses = List.of("Spring", "Spring Boot", "API" , "Microservices","AWS", "PCF","Azure", "Docker", "Kubernetes");
courses
courses.stream().sorted().forEach(System.out::println)
courses
courses.stream().sorted().forEach(System.out::println)
courses.stream().sorted(Comparator.naturalOrder()).forEach(System.out::println)
courses.stream().sorted(Comparator.reverseOrder()).forEach(System.out::println)
courses.stream().sorted(Comparator.comparing(str -> str.length())).forEach(System.out::println)
numbers
courses
courses.stream().map(x -> x.length()).collect(Collectors.toList())
numbers.stream().map(x -> x*x).collect(Collectors.toList())
Supplier<String> supplier = () -> {return "Ranga";};
Consumer<String> consumer = (str) -> { System.out.println(str);System.out.println(str);};
numbers.stream()
List<Integer> numbers = List.of(12, 9, 13, 4, 6, 2, 4, 12, 15);
numbers.stream()
Stream.of(12, 9, 13, 4, 6, 2, 4, 12, 15).count()
Stream.of(12, 9, 13, 4, 6, 2, 4, 12, 15).reduce(0, Integer::sum)
Stream.of(12, 9, 13, 4, 6, 2, 4, 12, 15)
int[] numberArray = {12, 9, 13, 4, 6, 2, 4, 12, 15};
Arrays.stream(numberArray)
Arrays.stream(numberArray).sum()
Arrays.stream(numberArray).average()
Arrays.stream(numberArray).min()
Arrays.stream(numberArray).max()
IntStream.range(1,10)
IntStream.range(1,10).sum()
IntStream.rangeClosed(1,10).sum()
IntStream.iterate(1, e -> e + 2).limit(10).sum()
IntStream.iterate(1, e -> e + 2).limit(10).peek(System.out::println).sum()
IntStream.iterate(2, e -> e + 2).limit(10).peek(System.out::println).sum()
IntStream.iterate(2, e -> e * 2).limit(10).peek(System.out::println).sum()
IntStream.iterate(2, e -> e * 2).limit(10).boxed().collect(Collectors.toList())
Integer.MAX_VALUE
Long.MAX_VALUE
IntStream.rangeClosed(1,50).reduce(1, (x,y)->x*y)
LongStream.rangeClosed(1,50).reduce(1, (x,y)->x*y)
LongStream.rangeClosed(1,50).reduce(1L, (x,y)->x*y)
LongStream.rangeClosed(1,10).reduce(1, (x,y)->x*y)
LongStream.rangeClosed(1,20).reduce(1, (x,y)->x*y)
LongStream.rangeClosed(1,40).reduce(1, (x,y)->x*y)
LongStream.rangeClosed(1,50).mapToObj(BigInteger::valueOf).reduce(BigInteger.ONE, BigInteger::multiply)
courses.stream().collect(Collectors.joining(" "))
courses.stream().collect(Collectors.joining(","))
"Spring".split("")
courses.stream().map(course -> course.split("")).collect(Collectors.toList())
courses.stream().map(course -> course.split(""))
courses.stream().map(course -> course.split("")).flatMap(Arrays::stream).collect(Collectors.toList())
courses.stream().map(course -> course.split("")).flatMap(Arrays::stream).distinct().collect(Collectors.toList())
List<String> courses = List.of("Spring", "Spring Boot", "API" , "Microservices","AWS", "PCF","Azure", "Docker", "Kubernetes");
List<String> courses2 = List.of("Spring", "Spring Boot", "API" , "Microservices","AWS", "PCF","Azure", "Docker", "Kubernetes");
courses.stream().flatMap(course -> courses2.stream().map(course2 -> List.of(course,course2))).collect(Collectors.toList())
courses.stream().flatMap(course -> courses2.stream().map(course2 -> List.of(course,course2))).filter(list -> list.get(0).equals(list.get(1))).collect(Collectors.toList())
courses.stream().flatMap(course -> courses2.stream().map(course2 -> List.of(course,course2))).filter(list -> !list.get(0).equals(list.get(1))).collect(Collectors.toList())
courses.stream().flatMap(course -> courses2.stream().filter(course2 -> course2.length()==course.length()).map(course2 -> List.of(course,course2))).filter(list -> !list.get(0).equals(list.get(1))).collect(Collectors.toList())
courses.stream().filter(courses -> courses.length()>11).map(String::toUpperCase).findFirst()
courses.stream().peek(System.out::println).filter(courses -> courses.length()>11).map(String::toUpperCase).peek(System.out::println).findFirst()
courses.stream().peek(System.out::println).filter(courses -> courses.length()>11).map(String::toUpperCase).peek(System.out::println)
$4.findFirst()
List<String> courses = List.of("Spring", "Spring Boot", "API" , "Microservices","AWS", "PCF","Azure", "Docker", "Kubernetes");
courses.replaceAll( str -> str.toUpperCase())
List<String> modifyableCourses = new ArrayList(courses);
modifyableCourses.replaceAll(str -> str.toUpperCase())
modifyableCourses
modifyableCourses.removeIf(course -> course.length()<6)
modifyableCourses
Creating a Custom Functional Interface and Creating a Lambda Expression matching it!
Clarify on Passing Behavior as a Parameter.
Collectors.toMap(key, value)
What are the constraints in using parallel() on the Streams?
collect(ArrayList::new, ArrayList::add, ArrayList::addAll)
partitioningBy
Behavior Parameterization
-> Tracing Performance of methods -> Pass function to track as a parameter
-> Externalize Sort Behavior as a parameter
Function Composition
Design Patterns
Play based on Position:
Lambda Expressions in Unit Tests => assertThrows
Currying f(x,y) = (g(x))(y)
Map Operations