Java is a programming language used by certain programs (you might run one) and certain webpages (you might occasionally view one). If you run such a program on your PC or visit such webpages you need it.
If you don't need it, you can safely delete it (uninstall all versions you see from control panel).
If you do need it, it's best to update.
If you're not sure delete it and wait for a call to reinstall it. Then you know what it is for.
What is JAVA and if I am just a plain old computer user for things such as searches and email do I need it and if it is already on my computer should I update it when asked or should I delete it from my computer ???