Java is one of the most popular and commonly used programming language in the world. It's a de facto standard. According to Oracle, 3 billion devices run on Java.
Java is a solid core language. Web and non-web environments, all operating systems, all types of devices...you’ll find Java everywhere. For those in favour of learning Java first, a key factor is that it teaches you to think like a programmer. You’ll learn the language, but you’ll also learn some key underpinnings of programming as well. It’s also an object oriented programming (OOP) language. Learning OOP requires students to master a certain level of logic. You have to learn how to think through processes in both the specific and the abstract. Again, that provides a good base for learning programming in general.
Another reason to learn Java is that Java is a mature language. Java has been around since 1995. In other words, in the programming world, it's been around a long time. How does that help? If you're new to programming or just new to Java, nearly any problem that you will run into has been run into by someone else. Any question you can ask has already been asked, answered, and posted online in some programmer community. There are loads of resources available to help you if you get stuck on a task.