Yosemite & Netbean: Display Issues : the JDK (Java Development Kit) installed on Retina Display is “jdk 1.6.0″ and the GUI rendering of “Netbean 8.0.1″ require “jdk 1.7″ to fix this issues upgrade the java on your macbook.
visit https://java.com/en/ and follow the steps.
maybe you would want to check the JDK on your machine before you update..? go to folder Macintosh HD ▸ Library ▸ Java ▸ JavaVirtualMachines
there could be other display issuse: check this older blog