mh_installjar: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/mh_installjar - from package: maven-repo-helper

You may install the required package with command apt-get install {package}
Error in other languages:
mh_installjar: bevel nie gevind nie
mh_installjar: comandă negăsită
mh_installjar: comando não encontrado
mh_installjar: commande introuvable
mh_installjar: command not found
mh_installjar: käsku ei ole
mh_installjar: không tìm thấy lệnh
mh_installjar: komanda nerasta
mh_installjar: Kommando nicht gefunden.
mh_installjar: kommandot finns inte
mh_installjar: komut yok
mh_installjar: nie znaleziono polecenia
mh_installjar: níor aimsíodh an t-ordú
mh_installjar: no se encontró la orden
mh_installjar: no s'ha trobat l'ordre
mh_installjar: opdracht niet gevonden
mh_installjar: parancs nem található
mh_installjar: perintah tidak ditemukan
mh_installjar: príkaz nenájdený
mh_installjar: příkaz nenalezen
mh_installjar: команда не найдена
mh_installjar: командата не е открита
mh_installjar: 命令找不到
mh_installjar: コマンドが見つかりません