Java is currently one the most well-known programming languages worldwide. This programming language is developed by Sun Micro-systems and is very powerful coding language.
Like any other coding language, you will have to learn the basics and ones that is established, you will need to study further to move up from a novice to an expert. These days allot of websites and applications use Java as part of the setup and will not function unless Java is not installed to run these applications or websites.
For more on where to download Java, you can visit https://www.java.com/en/download/