Infrastructure

Rob and I discussed the process to upgrade the system. We think those steps can be done manually.

I searched on the internet and found people always installed openjdk 1.8 through a ppa:
1. sudo add-apt-repository ppa:openjdk-r/ppa
(if the add-apt-repostiory command is not found, please do "sudo apt-get install software-properties-common")

1. sudo apt-get update

2. sudo apt-get install openjdk-8-jdk

3. sudo update-alternatives --config java

4. sudo update-alternatives --config javac

5. sudo update-alternatives --config keytool

Make system use openjdk-1.8:
1. Make tomcat use openjdk-1.8 - at the /etc/init.d/tomcat7 file, change the function

find_openjdks()
{
for jvmdir in /usr/lib/jvm/java-8-openjdk-*
do
if [ -d "${jvmdir}" -a "${jvmdir}" != "/usr/lib/jvm/java-8-openjdk-common" ]
then
OPENJDKS=$jvmdir
fi
done
for jvmdir in /usr/lib/jvm/java-7-openjdk-*
do
if [ -d "${jvmdir}" -a "${jvmdir}" != "/usr/lib/jvm/java-7-openjdk-common" ]
then
OPENJDKS="${OPENJDKS} ${jvmdir}"
fi
done
for jvmdir in /usr/lib/jvm/java-6-openjdk-*
do
if [ -d "${jvmdir}" -a "${jvmdir}" != "/usr/lib/jvm/java-6-openjdk-common" ]
then
OPENJDKS="${OPENJDKS} ${jvmdir}"
fi
done

}

1. Make Apache jk module use openjdk-1.8, in the /etc/libapache2-mod-jk/workers.properties (or /etc/apache/workers.properties file):
   workers.java_home=/usr/lib/jvm/java-8-openjdk-amd64

2. Restart apache

3. Restart tomcat