update-alternatives --list java
sudo update-alternatives --install /usr/bin/java java /opt/jdk-14.0.2/bin/java 0
sudo update-alternatives --install /usr/bin/javac javac /opt/jdk-14.0.2/bin/javac 0
sudo update-alternatives --set java /opt/jdk-14.0.2/bin/java
sudo update-alternatives --set javac /opt/jdk-14.0.2/bin/javac