I update my mac to big sur and java not found. i use java jdk 8
It will not work if you are in a restricted directory. Check below URL and look for answer by @Etresoft
you can raise a ticket in apple forums.
Note that Big Sur breaks the previous behaviour of the JAVA_HOME environment variable to pick the Java version used to run the command-line tools. If this matters to you, consider filing an bug report.
Or you can start install the Java new version