1) Install all of them, 1.6, 1.7, 1.8 in any order. I believe the last one installed determines which one will be used for browser plugins, I'm not going to care about changing those below.
2) Then, add to your bashrc or wherever:
export JAVA_HOME=$(/usr/libexec/java_home -v 1.7)
setjdk() {
export JAVA_HOME=$(/usr/libexec/java_home -v $1)
}Now you can:
$ java -version java version "1.7.0_51" Java(TM) SE Runtime Environment (build 1.7.0_51-b13) Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode) $ setjdk 1.6 $ java -version java version "1.6.0_65" Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609) Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode) $ setjdk 1.8 $ java -version java version "1.8.0" Java(TM) SE Runtime Environment (build 1.8.0-b132) Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)