How do I use the JAVA_OPTS environment variable?

JAVA_OPTS is the standard environment variable that some servers and other java apps append to the call that executes the java command.

For example in tomcat if you define JAVA_OPTS='-Xmx1024m', the startup script will execute java org.apache.tomcat.Servert -Xmx1024m

If you are running in Linux/OSX, you can set the JAVA_OPTS, right before you call the startup script by doing

JAVA_OPTS='-Djava.awt.headless=true'

This will only last as long as the console is open. To make it more permanent you can add it to your ~/.profile or ~/.bashrc file.