How do I install UniFi Network Controller and Oracle Java 8 on Raspbian 10 (buster)?

Question

I have a LABISTS Raspberry Pi 4 B Model B 4GB with Raspbian 10 installed (Buster). I've been trying to follow UniFi - How to Install and Update via APT on Debian or Ubuntu to install the Ubiquiti UniFi Network Controller to monitor my WiFi network, which uses a Ubiquiti access point. Unfortunately this software requires Oracle Java 8.

I've found various articles from a couple of years ago (e.g. UVC-NVR and JDK 1.8) which rely on oracle-java8-installer from webupd8team, but unfortunately this installation method is no longer available. I found this SO answer - E: Package 'oracle-java8-installer' has no installation candidate - which describes part of the manual installation process.

How do I complete the process?

Answer 1

I got it working so thought I would share the steps, some of which are similar to the steps in E: Package 'oracle-java8-installer' has no installation candidate.

1. Create an Oracle account

2. From the Oracle download page, download the Linux ARM v6/v7 Soft Float ABI 32bit version of Java because it's likely that you have a 64-bit kernel but 32-bit userland. Example: jdk-8u202-linux-arm32-vfp-hflt.tar.gz

3. Log in as root: sudo -i

4. Extract the tarball: tar -zxf jdk-8u202-linux-arm32-vfp-hflt.tar.gz -C /usr/lib/jvm

5. Link the correct name (required by the /etc/init.d/unifi startup script): cd /usr/lib/jvm; ln -s jdk1.8.0_202 jdk-8-oracle-arm32-vfp-hflt

6. Optional, not required by UniFi: Set JAVA_HOME for all users: echo "export JAVA_HOME=/usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt" > /etc/profile.d/java.sh

7. Install the new versions of Java (JDK and JRE, because the JRE is the one that the init.d script looks for):

    update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt/bin/java 100
    update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt/jre/bin/java 110
   

Now I can run the command I wanted to run in the first place: service unifi start

Then I can access the web interface on http://<IP address of Pi>:8080.

I hope this answer helps you to install Oracle Java 8 on their Raspberry Pi, especially if you're trying to install it so that you can run UniFi Network Controller!