CLASSPATH error after configuring JAVA Environment

I'm installing BLFS 8.4
After configuring JAVA Environment (binary), when I reboot the system a message is being displayed:

-su: ${AUTO_CLASSPATH_DIR}: invalid variable name.
-su: ${AUTO_CLASSPATH_DIR}: invalid variable name.

echo $CLASSPATH shows "."
I have set:
AUTO_CLASSPATH_DIR=/usr/share/java
JAVA_HOME=/opt/jdk
as per the book.
All the certificates are displayed properly.

Please help. Thank you.