antlr-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 CentOS possible default full paths are:

/usr/bin/antlr-java - from package: antlr

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

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