Functional Programming in Java When, Why and How? by Alasdair Collinson

Is functional programming useful or just a hype? Why should I even care? What good is it to me? Used correctly, functional programming concepts make code easier to read, understand and change. Used incorrectly, they will make a mess of your code. Let’s use them correctly, shall we?

For a while now, functional programming has been a hot topic in the Java community - though for many people it means stuff like “use Streams” and “write X as a lambda”. Functional programming is however so much more. In this session I’ll discuss some of the main concepts from functional programming that are relevant for Java developers. I’ll talk about when you want to use it - and when you probably don’t. Then I’ll show you ways to create useful functional code using a both core Java and a few helpful libraries.


Alasdair Collinson
From Senacor Technologies AG
A professional software developer by day, a nerd... Well, all the time, really. I love programming, I also love talking and thinking about programming. I'm fascinated by the culture surrounding programming and I immerse myself in that culture. And I like sharing what I have learned. I've spoken at conferences several times before about a range of different topics - some of them very technical, some of them less so. Mixing it up, that keeps it interesting for both me and my audience. Any you can be sure that everything I talk about is something that I'm really passionate about.

[ruixue]

0:45 3 things for functional programming
0:49 *declarative* - you write on what you want to have rather than how to get it
0:56 your functions are pure - 1:00 the output is defined only by the given explicit input, no side-effect
1:14 immutability -
1:24 *why*
1:31 *readability* 1:32 the intense of functional programming or *declarative programming* is 1:46 to make the code easier to read and easier to understand

2:07 describe *what*, not how

[stanpak]

I wished to get the point faster without memorizing complex examples and then not getting the point at the end. Examples should be brain-dead simple so they do not obscure the point that they are supposed to illustrate.

[SeanGildea]

Great talk, how did you learn so much about lambdas and functional programming? Was there a particular book? Any advice or direction is much appreciated!

[fredgotpub]

Real examples on how to do FP ! Good !

[vinodraut]

'How' part is nicely explained but 'Why' is not explained

[omnipoten]

Nice work . Although bit complicated for the novice. Also, please get your fact corrected at 13:04 You said that java isn't pass by value but pass by reference . However, this isn't correct . Java is indeed pass by value .