There have been a few questions about static methods with processing IDE. Because everything in Processing IDE is nested code static methods can be used only with static classes (Questions on static methods).
So are there options to circumvent this? Yes there is. As @GoToLoop explaned here Deeply-layered nested classes
You can move the class to regular .java file instead of .pde residing inside Processing IDE. You will lose compiler support from Processing IDE and most likely that code should be developed in external IDE like Eclipse.
Second option is to use a wrapper class. It’s not an optimal solution, but it can be done inside Processing IDE. Wrapper wraps around the target code and gives additional access methods. Wrappers have been used to simplify access. In this case they are used to store what in standard Java code would be in static variables and methods.