One of the biggest challenges for software programmers is incompatible operating systems. A program they write for PC isn't going to work on a Mac or a Blu-ray player.
That's why some software lets programmers write one program and run it on any system. The most widespread of these cross-platform systems is Java.
Thanks to the rise of cross-platform Web browsers and cloud computing, Java isn't as important as it once was. Still, without it certain websites, online games and even useful programs like LibreOffice won't run.
And you can't ignore that it's installed on an estimated 3 billion gadgets - including most new PCs you buy. Macs no longer have it installed by default.
Unfortunately, hackers have had a good few years picking apart Java for its security flaws. If you're running an older version of Java, your computer is in serious danger.
You need to make sure you have the most recent version of Java 7 installed. Oracle has Java 8 in the works, but it isn't released to the general public at this time. If you really want to try 8, you can grab it here (it's the one labeled JRE).
But that begs the question, do you even need Java? I'll tell you whether or not you do.
If you do install Java, make sure you set the security settings to be as safe as possible. Find out how in this helpful tip.