Java

Do I need Java? What is it? Do I need to update it?

Unless you uninstall Java, then YES, you need to update it. I normally assume Java is needed by everyone so install it on all machines. Many web based programs use it.

Java is an environment and a programming language. What you are downloading is the "runtime environment". It does two big things:

1. Since Oracle ⁄ Sun maintain the environment for Windows, Mac and Linux, it makes it much easier to write a Java program that will run on all three operating systems, because the program runs inside the environment which connects to the operating system.
2. The environment offers some protection from viruses and malware that could leak out into your system. It creates a barrier.

Updates are critical because they patch holes in the barrier that are being exploited by malware. Assume that every patch closes a dozen different holes being actively exploited by malware. Many programs, particularly web based programs require Java so it is likely that if you use lots of different software or do many things on the web you will run into the need for Java.