How-to articles, tricks, and solutions about FIREFOX
Class has been compiled by a more recent version of the Java Environment
If you get the error "class has been compiled by a more recent version of the Java Environment", it means that you are trying to run a class file that was compiled with a newer version of Java than the one you have installed.
Selenium using Python - Geckodriver executable needs to be in PATH
If you are using Selenium with the Firefox web browser and you see the error message "Geckodriver executable needs to be in PATH," it means that the Selenium Python library cannot find the geckodriver executable on your system.