When I move over a class name all the other places that that class name shows up are highlighted. When I hover over a variable it does the same thing with different places that
My answer is too late but it might be useful for someone else ,, In Neatbeans Tools >> Options >> Fonts & Colors >> Language (Java) >> Mark occurrences .
It is Language-specific. You have to go to Syntax > Change a Language and modify the "Mark Ocurrency" color.
Know more: How to change the highlight variable color in NetBeans IDE ?
I found this theme generator - helped me with my own color theme.
Below link to the online netbeans color theme generator
Net Beans theme builder