Eclipse + Java JDK 8 and Installing wpilibj to Java
To install Eclipse:
https://www.eclipse.org/downloads/download.php?file=/oomph/epp/2018-09/R/eclipse-inst-win64.exe
Go to the link above to download an .exe file to install eclipse.
Once you have downloaded double-click on it so that it opens. If you already have Java installed you will not get a notification about that and you should skip the next slide.
If you don’t have Java installed you will get a message about it and you should skip the part about installing Java.
To download Java:
Go to the following link: https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Find Java SE Development Kit 8u191 and accept the license agreement. Then download the file corresponding to your system. Ex: windows 32-bit or windows 64-bit.
After you’ve downloaded this file, you should double-click on it and let it run. After you have Java installed, you should go back to eclipse, shut it down, and start it back up again so it can detect the Java files on your machine.
To set up Eclipse:
Once you have loaded eclipse and you see this screen ->

Click on Eclipse IDE for Java Developers and install that.
How to add wpilibj to Eclipse:
Select "Help"
Click "Install new software".
From here you need to add a software update site, the location where the plugins will be downloaded. Push the "Add..." button then fill in the "Add Repository" dialog with:
Name: FRC Plugins
Location: http://first.wpi.edu/FRC/roborio/release/eclipse/
Click "OK".
Here is also a link to a presentation that explains how to install Eclipse and all of the components needed for FRC: https://docs.google.com/presentation/d/1OfyoyTwO-1jQxxWsQXvhBOs1AeCMFUFYK9ac1U5TmYY/edit?usp=sharing