java: 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/jvm/java-1.5.0-gcj-4.8-amd64/bin/java - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre/bin/java - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/bin/java - from package: gcj-4.9-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre/bin/java - from package: gcj-4.9-jre-headless
/usr/lib/debug/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java - from package: openjdk-7-dbg
/usr/lib/jvm/java-7-openjdk-amd64/bin/java - from package: openjdk-7-jre-headless
/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java - from package: openjdk-7-jre-headless

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

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