Java is a computer programming language.
Java software runs on laptops to data centers, game consoles to scientific supercomputers. There are 930 million Java Runtime Environment downloads each year and 3 billion mobile phones run Java.
If you disable Java some of your programs may not run the way you expect them. Java's finger is in a lot of pies. Example: Java is often used for website animation.
"Java" could be considered a threat because it is an "open" platform meaning there is no overseeing governing body that controls anything and everything programed using Java.