Jre
A: No. The JDK includes a complete JRE (and often a "server" optimized JRE). If you install the JDK, you can run Java programs.
Java 8 remains the most widely used version in legacy enterprise systems. It introduced Lambda expressions and is often the default version many users still try to download. it is smaller.
Download the (Runtime) or JDK (Development Kit) from your chosen vendor (e.g., Adoptium). Most modern distributions only distribute the JDK because it is modular, but if a "JRE only" option exists, it is smaller. it is smaller.