In /usr/bin/jh_clean line 7:
    rm -f `cat debian/.javahelper_clean` debian/.javahelper_clean
          ^----------------------------^ SC2046: Quote this to prevent word splitting.
          ^----------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
    rm -f $(cat debian/.javahelper_clean) debian/.javahelper_clean

For more information:
  https://www.shellcheck.net/wiki/SC2046 -- Quote this to prevent word splitt...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...