issue #1048: java 8 install: skip confirmation, add comment, add additional symlink

toolset/setup/linux/languages/java8.sh

@@ -3,12 +3,15 @@
 sudo add-apt-repository -y ppa:webupd8team/java
 sudo apt-get update
 echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | sudo /usr/bin/debconf-set-selections
-sudo apt-get install oracle-java8-installer
+sudo apt-get install -y oracle-java8-installer
+
+sudo ln -s /usr/lib/jvm/java-8-oracle /opt/java8
 
 # set Java 7 (OpenJDK) as the default, as previously.
 sudo update-alternatives --set java /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
 sudo update-alternatives --set javac /usr/lib/jvm/java-7-openjdk-amd64/bin/javac
 
+# try to make sure all JDK binaries default to OpenJDK 7, not Java 8.
 update-alternatives --get-selections | grep java-8 | sed -e 's/java-8-oracle/java-7-openjdk-amd64/' | while read line
 do
   l=(${line// / })
@@ -18,3 +21,4 @@ do
     sudo update-alternatives --set $n "$p"
   fi
 done
+