jcf-dump: 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/jcf-dump - from package: gcc-java

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

On Debian possible default full paths are:

/usr/bin/jcf-dump - from package: gcj-jdk

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

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