Functional Programming in Java : Java Lambdas and Streams
What you'll learn
- Functional Interfaces - what they are and their relationship to lambda expressions.
- Lambdas - anonymous inner class syntax versus lambda expressions.
- Functional Interfaces from the API - sample code explaining Predicate/BiPredicate, Consumer/BiConsumer
- Functional Interfaces from the API - sample code explaining Supplier, Function/BiFunction
- Functional Interfaces from the API - sample code explaining UnaryOperator, BinaryOperator
- Method References - their relationship with lambdas. Different types of method references explained with code - bound, unbound, static and constructor.
- Method References - how the context helps in understanding them.
- Streams - what they are, stream pipelines and stream laziness.
- Streams - Terminal operations.
- Streams - Terminal operations - reduce, collect() explained with code examples.
- Streams - collect() using API collectors explained with code examples e.g. CollectorsDOTtoMap(), CollectorsDOTgroupingBy() and CollectorsDOTpartitioningBy()
- Streams - Intermediate Operations explained with code examples e.g. filter(), distinct(), limit(), map(), flatMap() and sorted().
- Streams - stateful and short-circuiting intermediate operations explained.
- Streams - Primitive Streams - how to create them, what their API's look like and how to map between them.
- Streams - mapping between Object streams and primitive streams and vice versa.
- Optionals - what they are and why they are useful. Sample code demonstrating their use.
- Parallel Streams - how to create them. Sequential versus parallel stream processing.
Requirements
- Intermediate Java. Whereas my "Java 8 OCA (1Z0-808) Course" starts at the beginning, this assumes that the learner has a reasonable level of Java.
- To make understanding lambdas easier, a familiarity with anonymous inner classes would help. That said, lambdas are contrasted with anonymous inner class syntax in the course.
Description
IMPORTANT - My advanced Java course: Java 21, Java 17, Java 11, Java 8 (adv.) and Spring Boot 3, contains this course as a subset. My advanced Java course contains an over 31 hours of content and is worth checking out before investing in this this course (as it is, in my opinion, better value for money).
Sample reviews:
"Excellent course on Java Lambdas and Streams. Doctor Sean Kennedy clearly explained all concepts and techniques using great amount of examples. The assignments reflected what we learned in the course. Thank you Doctor Sean Kennedy!" [Jing H]
"This course provides hands-on knowledge on how to work with functional programming in java. From Lambdas to Optionals, the way Java 8 api adds this new features is really a key factor to productivity and performance." [Calebe O]
"Concise, easy to follow, very useful. Very talented lecturer." [Luka K]
"Sean described lambdas and streams ,covered all the topics in detailed level." [Kalpana M]
"Very good course, learnt many new things. Dr Kennedy should bring out more courses." [Vasudha S.]
"The course is very well-organized and clearly presented. Thank you, Dr. Seán Kennedy." [Ricardo R.]
"Super course, great help with this important area of Java programming." - David F.
"Excellent course and teacher's explanations." - E. A.
"Fantastic course, very engaging and delivered in an easy to understand manner." - Gary W.
"Excellent Course, the concepts are explained in a clear & concise manner making it easy to understand." - Bv
"Content explained clearly and punctually. Recommended" - Daniel M.
This course is a systematic approach to explaining in both notes format and code examples, lambda expressions and streams in Java. All the code samples are included (on my GitHub repo).
Topics include:
Lambdas:
Functional Interfaces
Lambdas and their relationship to Functional Interfaces
Lambdas in code using a custom Functional Interface
Lambdas in code using the pre-defined API Functional Interfaces:
Predicate/BiPredicate
Supplier
Consumer/BiConsumer
Function/BiFunction
UnaryOperator and BinaryOperator
final and "effectively final"
Method References:
bound
unbound
static
constructor
context and it's effect in understanding method references
Assignment to reinforce the content
Streams:
Pipelines
Laziness
Creating streams
Terminal operations:
reduce()
collect()
Collectors.toMap()
Collectors.groupingBy()
Collectors.partitioningBy()
Intermediate operations:
filter(), distinct(), limit()
map(), flatMap(), sorted()
Primitive streams:
Creating
API
Functional Interfaces
Mapping between primitive streams
Mapping between primitive streams and Object streams and vice versa
Optionals
Parallel streams
Assignment to reinforce the content
This course is geared towards Java Certification i.e. the Predicate lambda sections would suit Java 8 OCA (1Z0-808). The remaining lambda sections and the streams sections would suit any version of Java OCP. This course explains the concepts through small, simple, targeted code examples.
Note that, my other 2 courses, namely "Java 8 OCA (1Z0-808) Certification - Master the Fundamentals" and "Java 21, Java 17, Java 11, Java 8 (advanced) and Spring Boot" have both been selected for the Udemy Business portfolio (only the top 3% of courses qualify).
For those who don't know me, I am a lecturer since 2002 and have taught the Java OCA and OCP syllabii since 2013 on behalf of a highly regarded software company. On completion of the courses with me, graduates then face the company's own internal Java Certification exam (similar in style to Oracle's). I have no visibility into the questions they will face. It is a 3 hour long intensive exam. The company are delighted with the pass rate (100% since year 1). I love teaching and this course has all my experience in explaining lambdas and streams in Java.
Who this course is for:
- Anyone interested in learning Lambdas and Streams (the Functional Programming aspects of Java 8).
Instructor
Hi, Seán here. I worked in industry for 13 years in FinTech and Telecoms. I have been a lecturer since 2002 and have a PhD in IT. I am Java certified to both OCA and OCP levels. I have taught the OCA/OCP syllabii since 2013 on a Level 9 Masters course on behalf of Ericsson. The popular Java certification tool Enthuware link to my YouTube channel in their explanations. I have recently co-authored (with Maaike van Putten) two books on Java: "Learn Java with Projects" and "Java Memory Management: A comprehensive guide to garbage collection and JVM tuning".