After you’ve learned the basics of computer science, you’ll be ready to learn a programming language. Java is a high-level object-oriented programming language which is platform independent and can be run on any mobile, web or desktop applications.
Theoretically, it is true that with hard work, effort and right direction one can become an expert in Java programming. But practically it would help if you know one or two core programming languages to understand the jargon easily. Learning the basics of computer science will not be enough. If you have prior knowledge of C language and the concepts, learning Java becomes easier.
Java can be downloaded easily and anyone can download the JRE and run the Java program. There are many tutorials available on the tutorialspoint website where you can learn Java from scratch even without much coding background.