Another workaround is to run the Windows version of Matlab in a virtual machine on your Mac. Retina support (called "Hi-DPI" in Windows parlance) works mostly fine out of the box on the Windows side for R2014a on Windows 7. (You just need to adjust your font sizes. And the ribbon is displayed really small.) It doesn't seem to have the stability issues that running OS X Matlab against a newer MATLAB_JAVA does.
I'm running OS X 10.9.2, Windows 7 SP1 in a VM under Parallels Desktop 9, Matlab R2014a.