Updating to OpenJDK 11

Download OpenJDK's JDK 11 from https://jdk.java.net/11/

On Windows (10):

1. extract zip to Program Files/Java/
2. change JAVA_HOME environmental variable to point to the new JDK

On Ubuntu (16.04) for version 11.0.2:

1. unpack tar.gz to /usr/lib/jvm/ (command taken from OpenJDK installation guide)
   

   sudo tar xvf openjdk-11*_bin.tar.gz --directory /usr/lib/jvm/

2. update alternatives to be able to switch between other java installations (command taken from DZone guide)
   

   sudo sh -c 'for bin in /usr/lib/jvm/jdk-11.0.2/bin/*; do update-alternatives --install /usr/bin/$(basename $bin) $(basename $bin) $bin 100; done'
   sudo sh -c 'for bin in /usr/lib/jvm/jdk-11.0.2/bin/*; do update-alternatives --set $(basename $bin) $bin; done'

3. don't forget to update the JAVA_HOME environmental variable if you use maven