Sharing environment variables between zsh and bourne shell (for crontab)

I set JAVA_HOME in .zshrc: export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64/jre/ which is fine for interactive programs. But I have JVM programs running via cron, which uses Bourne shell. The bourne shell programs keep giving me this: groovy: JAVA_HOME is not defined correctly, can not execute: /usr/lib/jvm/default-java/bin/java What's the neatest way to solve this? I don't remember having to worry about this before. Currently I'm setting JAVA_HOME on every crontab entry which is burdensome and redundant.