jconsole: 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 Debian possible default full paths are:

/usr/lib/debug/usr/lib/jvm/java-7-openjdk-amd64/bin/jconsole - from package: openjdk-7-dbg
/usr/lib/jvm/java-7-openjdk-amd64/bin/jconsole - from package: openjdk-7-jdk

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

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