I'm kind of new in java, so probably my question is too obvious. The other day looking into /usr/lib/jvm/java-1.8.0-openjdk- in my Fedora, I notice some duplicated binaries like bin/java and jre/bin/java.

I read about the difference between JRE and JDK, but I don't get why is necessary to keep both binaries if we only use one of them. 

Hope you can help me to understand a little more.

Thanks a lot.