Well, it's not true that Java is mandatory to learn Selenium. But you should be aware of the know-how of other programming languages at least. Even if you know one of either: JavaScript, Python, Ruby, C# then you can learn Selenium easily. But, Java and Python are the easiest and best options for performing testing with Selenium. Be it WebDriver or Grid, you need to write scripts in one of the programming languages. Hence it is a basic necessity. It is not that difficult to learn the concepts either. You don’t need to learn everything about Java at the start. You can start off from the basics, and over a period of time, you will itself start picking up other concepts. Since java is the most widely accepted language for Selenium testing, I would recommend you to learn java. To learn Selenium you can take up the following Selenium Training Course.
You will get a basic introduction to required Java concepts in the video below:-
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