Palette symbols

An IlvPaletteSymbol can only exist within a palette.
You need first to create an IlvPalette, then set its root category (and more categories if needed), and finally add the symbol to a category in the palette:
IlvPalette palette = new IlvPalette();
palette.setRootCategory("Root");
IlvPaletteSymbol psymbol = palette.addSymbol(palette.getRoot(),"symbol1");
The symbol needs a CSS file and other resources.
You must make sure that the CSS file and the resource files are in the class path; otherwise, you must use the IlvPaletteManager.
Assuming that all the required files are in the class path:
psymbol.setName("Symbol");
psymbol.setClassName("Symbol");
psymbol.addResource(css);
psymbol.setCSSResourceName(css);