I've been setting Windows environment variables (like JAVA_HOME) every time I installed a Java update. (As per Environment variables for java installation).
However, I've recently noticed that Java updates add C:\ProgramData\Oracle\Java\javapath; to the System Path (not the User Path). I removed JAVA_HOME, etc from my User Path, and java -version seems to work from any directory.
Does that mean that it is not necessary to do that simple but annoying task with each Java update?
That depends on what you are trying to do.
Generally, you don't need JAVA_HOME to run a Java app. Adding the location of the Java binaries to the PATH is sufficient for Windows to find and execute them.
However, e.g. a lot of application servers like Tomcat and build tools like Gradle will use JAVA_HOME to determine the location of your Java installation.