In a comment under @Thilo's answer, @mobibob asked how to set JAVA_HOME in your .bash_profile on a Mac. Answer:
export JAVA_HOME=`/usr/libexec/java_home`
This will dynamically assign to JAVA_HOME the location of the first JDK listed in the "General" tab of "Java Preferences" utility.
See Apple Technical Q&A 1170: https://developer.apple.com/library/content/qa/qa1170/_index.html
EDIT:
If you prefer parentheses to backticks for command substitution, this also works:
export JAVA_HOME=$(/usr/libexec/java_home)