Java errors in Processing "Unsupported major.minor version 52.0" Windows 10
I'm on a Windows 10 system, and am following the OpenBCI getting started guide. The OpenBCI libraries and GUI directory have been placed where they should be.
I'm snagged on a pure software issue with Processing 2.2.1 (Processing 3 doesn't work with the OpenBCI code, AFAIK). Trying to run any of the .pde files from the OpenBCI repo throws an error after the GUI window opens, after I select "Synthetic" as the data source and then click "Start System".
The error is: Unsupported major.minor version 52.0
Googling that suggests that it means that the relevant java code was run with a version that is too old compared to the version that compiled it. However, if I understand processing correctly, then all of its Java is self-contained, so I don't see how this could be. The java on my system is the current version, in any case.
Any help is, of course, greatly appreciated.

Comments
I agree with the OP that Processing 3 doesn't work with OpenBCI code. I am also getting the unsupported manjor.minor version error as below:
java.lang.RuntimeException: java.lang.UnsupportedClassVersionError: org/gwoptics/graphics/graph2D/backgrounds/IGraph2DBackground : Unsupported major.minor version 52.0
Is it an issue with gwoptics?
Could someone please help us out with this?
The issue is with the gwoptics library. The fix is to just download the latest version from the website, and use that directory as the library.
gwoptics website: http://www.gwoptics.org/processing/gwoptics_p5lib/
gwoptics zip file: http://www.gwoptics.org/processing/gwoptics_p5lib/download/gwoptics.zip
Hope this helps.
Had openJDK 7 installed, so I removed that and installed Java 8 using this link:
http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html
After doing that, I was able to get the GUI to open. The first time I ran it, it froze up my system. Had to do a hard restart. Second time, it worked ... so far. Was able to go into synthetic mode and "stream" synthetic data. Fingers crossed, it will keep working. It sure does output a lot of lines to the terminal though. It'd be nice if that was in the GUI instead.