I think ver0man has right.

https://www.codewars.com/kata/array-dot-diff

I used almost the same code, only changed variable name...

You're missing a '}' in the test cases. It wasn't obvious at first, because I thought it came from my solution code.
But other than that thanks for the translation. I had fun :)

You suggestions are welcome.

Do you mean that this kata is duplicated here at Codewars? What is redundant for you? Could you be more specific?

Thanks. Glad you liked it)

When I run testcases, even with the solution's skeleton, I get the following error:
/ConversionTest.java:13: error: reached end of file while parsing
}
^
1 error

java.lang.RuntimeException: /ConversionTest.java:13: error: reached end of file while parsing } ^ 1 error at codewars.runners.java$compile_and_load.doInvoke(java.clj:85) at clojure.lang.RestFn.invoke(RestFn.java:439) at codewars.runners.java$fn__572.invoke(java.clj:110) at clojure.lang.MultiFn.invoke(MultiFn.java:227) at codewars.runners$run.invoke(runners.clj:22) at codewars.core$_main$fn__634.invoke(core.clj:40) at clojure.lang.AFn.call(AFn.java:18) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.lang.Thread.run(Thread.java:745)