exercism/java

Lee Stewart

@zantetsuken88

I wonder if anyone can help me out. Complete newbie to java - although I've completed the codecademy course (which is super short and basic). But I'm having trouble even starting the exercism course. I'm on the 2nd exercise and I just have no idea where to begin.

Norbert Melzer

@NobbZ

Which one is the second for you?

Lee Stewart

@zantetsuken88

It's the 'Twofer' task

I actually managed to get the first two tests to pass now. But yeah in the beginning it's a bit overwhelmingly contextless and I had no idea how to start

Lee Stewart

@zantetsuken88

ok I did it yayy http://exercism.io/submissions/898fb26a5e0c49a7a896df29dd59e3af

Sam Warner

@sjwarner-bp

Hey @zantetsuken88, sorry to hear you found it overwhelmingly contextless - do you have any tips as to how we might improve it? :smile:

Lee Stewart

@zantetsuken88

@sjwarner-bp That task has a huge README on TDD which is great, really helpful to understand how to work your way through these tasks in general. But at that stage I wasn't ready for the task itself. I needed a nudge in the right direction.

As it was, it turned out I just needed to understand that if I simply deleted the exception and return the string in the test, that the test would pass.

Once I understood what exactly the test was doing and what it was expecting, (and that I needed to return the value rather than print it), I've been pretty much fine ever since.

Sam Warner

@sjwarner-bp

Thanks for the feedback @zantetsuken88 - I'll relay this info to the other track maintainers and see if we can improve this for future users!

If you have any ideas of what you'd like to see added as hints to the readme / anything else for that exercise, feel free to open a PR for it too - we love having the community grow and raise these issues!

Norbert Melzer

@NobbZ

I glanced over the tests implementation, and I am wondering why there is an object created, also I'm wondering if there are better alternatives than passing null for "whatever the default value is".

Norbert Melzer

@NobbZ

I think using a static object at this state of the track would be much easier for the student.

static class, sorry…

Sam Warner

@sjwarner-bp

Hi @NobbZ, you raise a good point. I think that the only reason we pass null is because that is what happens in the canonical data, but we could deviate (overloaded methods seem obvious here, but might be a more complex idea this early in the track).

As for static, one of our POLICIES is to prefer instance methods. I don't think this would simplify the exercise particularly, though maybe I am the wrong person to ask and we should seek a beginner's input.

Above, Lee has only expressed an issue with the README, something that we might add hints to. I'd be interested in seeing what the others thought here though :smile:

Norbert Melzer

@NobbZ

Then those policies needs to change, to be honest... There is no state in this object. It needs to have an instance for no obvious reasons. I think this is a bad example for the next API design lesson. I have to be honest though, it's a mostly functional mindset speaking here, I'm not sure about Javas idioms, but at least there's the Math class IIRC, which doesn't get instantiated as well.

Sam Warner

@sjwarner-bp

I certainly understand your point - this task is certainly one that requires no state (and a handful of others exercises also spring to mind), but it seems like we've implemented them all with some OOP in mind. It is interesting though, now you've brought this up I can certainly see a very obvious case for them. It might be (slightly) odd if we start new users on a track that begins more functionally (hello-world, two-fer) before becoming very OO, but definitely worth a discussion with the rest of the Java team. I'll ask around! :smile:

FridaTveit

@FridaTveit

@NobbZ if you have a look at the reference for that policy (https://github.com/exercism/java/issues/177#issuecomment-261291741) you can see we've had an extensive discussion around why we want to prefer instance methods. Basically this is because in Java it's considered best practice to write more object oriented code, unlike other more functional languages. So even though these small exercises could easily be implement using static methods, we want to use instance methods so that people learning Java get familiar with them as they'll be more useful later on when writing Java code in general. I hope that makes sense, though of course everything is up for discussion so feel free to open an issue if you still think it would be worth changing :)

Norbert Melzer

@NobbZ

As I said, I'm not aware of Javas idioms, so I totally have to trust you when you say its more idiomatic to have the overhead of useless allocations… At least I have to admit, that in functional languages its very common to copy (and therefore allocate) nearly every value on change ;)

Mpatziakoudi Katerina

@katmpatz

Hi!! I am student in Software Engineering and I really want to contribute in excersism :smile: !! I have already read the contribution guide and I have seen the open issues, but I realized that the majority of them have been implemented. I would like to contribute on code. I am thinking of implementing one of the existing exercises that have not been implemented in java or adding a new exercise. Do you have suggestions for something else that I could contribute or do you have some advice on adding exercises?If I decide to add an exercise that has not been implementing in java, should I open an issue to report which exercise I am going to add? Thank you!! :smile:

Sam Warner

@sjwarner-bp

Hi @katmpatz!! That's great to hear - we always like to get new contributors :smile:

All of the issues should be unresolved. Not all of them require an entire exercise to be implemented, some will be small changes - this can often be a good starting point! At the moment, most of the issues are about updating some of the tests we have. There is a pretty large range of issues to pick up at the minute :smile:

If you would like to implement an exercise that isn't completed in Java yet, the list can be found here. If you let one of the Java team know, we will be more than happy to open an issue and assign you to it, so no-one else will take the same thing!

Does that all make sense? I'm happy to discuss more questions any time :fireworks:

Mpatziakoudi Katerina

@katmpatz

Ok!I will start by trying to solve some open issues. Thanks for your response! :smile:

Sam Warner

@sjwarner-bp

No problem! There is normally someone on here that can answer questions 😊

Jeffrey Sander

@jssander

Could you recommend another open source java project to contribute to? Hopefully one with a relatively small and friendly community like this one.

Logan Stucki

@Smarticles101

deleted the xjava room just now, not sure why it was still open for so long

Victor Goff

@kotp

Thanks @Smarticles101

vincemizuki

@vincemizuki

does anyone know how to fix this error when fetching an exercise

java $ exercism download --exercise=matrix --track=java
Error: Get /solutions/latest?exercise_id=matrix&track_id=java: unsupported protocol scheme ""

Norbert Melzer

@NobbZ

What is the output of exercism configure 2>&1 | grep -- --api?

vincemizuki

@vincemizuki

im using exercism version 3.0.2

let me me check

exercism configure 2>&1 | grep -- --api returns blank

Norbert Melzer

@NobbZ

When you run only exercism configure, is there a line with an "API Base URL" at all? Maybe you can copy and paste the full ouput but remove/obfuscate the token please.

vincemizuki

@vincemizuki

blackbird exercism $ exercism configure 2>&1 | grep -- --api
blackbird exercism $

returning blank

this was working a few months ago

Norbert Melzer

@NobbZ

Since yesterday everything is different.

vincemizuki

@vincemizuki

but I can see exercism has been updated, so I've updated exercism in my terminal

I see

Norbert Melzer

@NobbZ

So lezts check for exercism configure 2>&1 | grep -v -- --token

vincemizuki

@vincemizuki

returns blank too

Norbert Melzer

@NobbZ

completely?

vincemizuki

@vincemizuki

yep

Norbert Melzer

@NobbZ

Have you reconfigured after updating?

vincemizuki

@vincemizuki

yep i did but i was getting an error saying a file already exists

let me delete the file and retry

Norbert Melzer

@NobbZ

NO!

Which file already exists?

Don't delete randomly

vincemizuki

@vincemizuki

deleting the exercism folder works. i've backed it up. works fine now

thanks

Norbert Melzer

@NobbZ

Just reading the full message and applying --workspace=… would have probably been easier

Lee Stewart

@zantetsuken88

Java mentoring seems to have ground to a halt again. I've got 3 extra exercises that have been submitted for a long time - possibly weeks - and it's been about a day and half since I submitted the last core exercise with no comments as of yet

Corey

@c1505

I am new to Java, but wondering why there isn't a main method in Java exercises and why the tests still work without it.

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