fastjar: command not found

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 CentOS possible default full paths are:

/usr/bin/fastjar - from package: libgcj

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/fastjar - from package: fastjar

You may install the required package with command apt-get install {package}

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