Hi Jayden,
I'm an Independent Advisor and consumer of Microsoft products just like you. Let me help you with your concern.
Java Auto Update is a feature of the Java runtime that keeps your Windows PC up-to-date on the latest Java releases.
You may refer to the below link for more details.
https://java.com/en/download/help/java_update.xml
Java runtime is an important component of some apps that you may have. You have to apply/download the update because it is in the updates that software fixes are made available to existing software installation. In that sense, it boost your PCs security.