switch to the ubuntu 18.04 base box

Vagrantfile

@@ -20,7 +20,7 @@ Vagrant.configure(2) do |config|
   end
 
   config.vm.define :nexus do |config|
-    config.vm.box = 'ubuntu-16.04-amd64'
+    config.vm.box = 'ubuntu-18.04-amd64'
     config.vm.hostname = nexus_domain
     config.vm.network 'private_network', ip: nexus_ip
     config.vm.provision :shell, path: 'provision/provision-base.sh'

provision/provision-nexus.sh

@@ -11,7 +11,7 @@ config_authentication='nexus'
 
 
 # install java.
-apt-get install -y default-jre
+apt-get install -y openjdk-8-jre-headless
 
 
 # add the nexus user.

provision/use-maven-repository-from-mvn.sh

@@ -10,7 +10,7 @@ mkdir -p tmp/use-maven-repository-from-mvn && cd tmp/use-maven-repository-from-m
 
 # install maven and the java development kit.
 sudo apt-get install -y maven
-sudo apt-get install -y default-jdk
+sudo apt-get install -y openjdk-8-jdk-headless
 sudo apt-get install -y xmlstarlet
 
 # setup the user maven configuration to use nexus as a mirror the
@@ -79,7 +79,7 @@ xmlstarlet ed --inplace -N pom=http://maven.apache.org/POM/4.0.0 \
   --name distributionManagement \
   --value '@@repositories@@' \
   pom.xml
-python -c "
+python3 -c "
 xml = open('pom.xml').read().replace('@@repositories@@', '''
     <repository>
       <id>nexus</id>