jdk replacement of lower version does not take effect

I want to change to jdk1.8, but it does not take effect after the change. Checking the environment variables is no problem. Later, the parties found that it might not be 1. Put JAVA_HOME at the top of the path . I think the reason is related to the path of the C drive. Maybe the jdk has changed some files or the registry and the lower version cannot take effect. , After the change, it is still useless.
In angrily 2. After uninstalling the high version of jdk11 , it is fine , for unknown reasons.