@pawel.kapala @curlyfry wow! Thanks. I really appreciate it.

Hi everyone!... I am confused about how to include java code in an application. Right now, my sources are separated in two folders: src/java and src/clojure. I want to import a class that I wrote from a clojure namespace, however, when I run lein javac or lein repl I receive an exception with a message telling me that the class was not found.

This is the import statement

And the stacktrace error message is this:

Exception in thread "main" java.lang.ExceptionInInitializerError at clojure.main.<clinit>(main.java:20) Caused by: java.lang.ClassNotFoundException: org.tempuri.Core, compiling:(scv2backend/component/signature_soap_client.clj:1:1)

From what I have read, first I should run lein javac to compile my java sources and the run lein repl, but for some reason isn't working.

@rcanepa might be an issue with your project.clj too, would be useful to see the relevant parts / all of it.

@dominicm right! ... I believe this is the important part:

Does running lein javac compile the clojure sources too?

Nope. Shouldn't need to. Might be worth looking around target for .class files

Ok, I will. Thanks @dominicm

I removed the import statement and the repl started without problems. Then I added back the import statement, reloaded the repl and everything worked fine again. That is very weird. I guess now the java sources are compiled so I can import them.

If I execute lein clean, I go back to the same problem as before.

Yeah, lein clean will clean up the target directory.

You might have a problem if you do lein repl then lein javac, you need to make sure javac finishes first. All I can think of

Hmm, you did do that

maybe someone else will know 🙂 ¯\(ツ)/¯

Yeah, I did that. Thanks anyway!

Why does f v are not resolved here :

(def mapset
  "works like a map but returns a set"
  [f v]
   (f v )
  ) 

Show an example of ^ being used. How would you call it and what would you expect?

you used def not defn

you are trying to define a function

^ thats it

thanks

hmm, when I do (mapset inc [1 1 2 2]) I see this error : ClassCastException clojure.lang.PersistentVector cannot be cast to java.lang.Number clojure.lang.Numbers.inc (Numbers.java:112)

you’re trying to call “inc” on a vector, which you cannot do.

you can see that it says, Vector cannot be cast to a Number

inc expects a number.

remember that excersizes 4,5,6 are considered “difficult” at that point and you can revisit them after reading the next two chapters

map can be a tough concept to immediately grasp onto if you haven’t seen it before

yep, I had to use map

now I have to find out how to make a set of a map

solved it

nice work

thanks

tomorrow I will take a look at the last two exercises.

I have a idea for the 5th one

I have to find a function that will do the recur several times I think

Am I on the right track that I have to change this function :

(defn better-symmetrize-body-parts
  "Expects a seq of maps that have a :name and :size"
  [asym-body-parts]
  (reduce (fn [final-body-parts part]
            (into final-body-parts (set [part (matching-part part)])))
          []
          asym-body-parts))  

for both exercise 5 and 6 of do things of the brave book ?