I'm trying to download antlr (a jar). These are the commands I used (for unix):

cd /usr/lib 

curl -O https://www.antlr.org/download/antlr-4.7.1-complete.jar

export CLASSPATH=".:/usr/lib/antlr-4.7.1-complete.jar:$CLASSPATH"

alias antlr4='java -Xmx500M -cp "/usr/lib/antlr-4.7.1-complete.jar:$CLASSPATH" org.antlr.v4.Tool'

However, when I run this line of code:

java org.antlr.v4.Tool

Unix gets angry and says:

Could not find or load main class org.antlr.v4.Tool 

What am I doing wrong? :(