@Override
            public void onAction(String name, boolean isPressed, float tpf) {
                if (isPressed) {
                    if (name.equals("overrideClear")) {
                        rootNode.clearMatParamOverrides();
                    } else if (name.equals("overrideGray")) {
                        rootNode.clearMatParamOverrides();
                        rootNode.addMatParamOverride(overrideGray);
                    } else if (name.equals("overrideWhite")) {
                        rootNode.clearMatParamOverrides();
                        rootNode.addMatParamOverride(overrideWhite);
                    } else if (name.equals("overrideYellow")) {
                        rootNode.clearMatParamOverrides();
                        rootNode.addMatParamOverride(overrideYellow);
                    }
                    System.out.println(rootNode.getLocalMatParamOverrides());
                }
            }
Test if {@link MatParamOverride}s are working correctly.

@author Kirill Vainer
jme3-examples/src/main/java/jme3test/material/TestMatParamOverride.java