What is my real Java version on macOS?

I use macOS Sierra. When I do:

java -version
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-468-11M4833)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-468, mixed mode)

it seems that my java version is 1.6.0.
But when I look at System Preferences I find that my version is Java 8 Update 144. I want to use an R package that needs Java >=8.0. What have I done wrong?

The Java found in your command line is the one used to compile when using command line, first, try export JAVA_HOME=$(/usr/libexec/java_home -v 1.8) then check if the correct version shows up using java -version if not reinstall the newest java and run the command again