What exactly are we wrapping in code tags? For example:

System.out.println(<code>resultTest</code>);
or
<code>System.out.println(resultTest);</code>

These issues with "null" showing up in the most unexpected places of a result are very annoying... Although I guess that is an issue with the CodeWars site as opposed to the kata.

I believe I have it figured out (trying with the Java version of this kata), but I keep getting an error with the test case and cannot submit the solution. Error description follows:

/Tests.java:8: error: cannot find symbol
assertThat(Kata.HighAndLow("8 3 -5 42 -1 0 0 -9 4 7 4 -4"), is("42 -9"));
^
symbol: method is(String)
location: class Tests
1 error

java.lang.RuntimeException: /Tests.java:8: error: cannot find symbol assertThat(Kata.HighAndLow("8 3 -5 42 -1 0 0 -9 4 7 4 -4"), is("42 -9")); ^ symbol: method is(String) location: class Tests 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) "

It looks to me as if whoever converted this kata over to Java didn't implement the "is(String)" properly, I bet it's an easy fix although I can't be sure.