We are introducing a change in JDK/JRE packages of our distro. This is triggered from the way a JRE is build in modern versions of Java (>9). We are introducing this change in Java 21. To sum it up instead of having JDK and JRE packages coexist in the same system we will be making them conflict. The JDK variant package includes the runtime environment to execute Java applications so if one needs compilation and runtime of Java they need only the JDK package in the future. If, on the other hand, they need just runtime of Java then JRE (or jre-headless) will work. This will (potentially) require a manual user action during upgrade: if you have both JDK and JRE installed you can manually install the JDK with pacman -Sy jdk-openjdk and this removes the JRE related packages. if you have both JRE and JRE-headless you will need to choose one of them and install it manually since they would conflict each other now. If you only have one of the JDK/JRE/JRE-headless pacman should resolve dependencies normally and no action is needed. At the moment this is only valid for the upcoming JDK 21 release.