For configuring alternatives, I follow a slightly different approach to @donniezazen's steps.
Below approach is useful for me as I frequently use other components during Java development.
sudo /usr/sbin/alternatives \
--install /usr/bin/java java /usr/java/jdk1.8.0_45/bin/java 20000 \
--slave /usr/lib/jvm/java_home_dir java_home_dir /usr/java/jdk1.8.0_45 \
--slave /usr/bin/javadoc javadoc /usr/java/jdk1.8.0_45/bin/javadoc \
--slave /usr/bin/javaws javaws /usr/java/jdk1.8.0_45/bin/javaws \
--slave ... add those you need ... keytool / orbd / servertool / rmiregistry ... etc
Full alternatives command is here
Also configure such that JAVA_HOME is switched each time alternatives is used.
sudo vim /etc/profile.d/sun-jdk.sh
# /etc/profile.d/sun-jdk.sh
#
# Set PATH for Sun JDK
export JAVA_HOME=`realpath /etc/alternatives/java_home_dir`
PATH=$JAVA_HOME/bin:$PATH
export PATH
Don't forget to make the script executable
sudo chmod +x /etc/profile.d/sun-jdk.sh