@Override
    public void adjustHeight(Vector2f xz, float delta) {
        List<Vector2f> coord = new ArrayList<>();
        coord.add(xz);
        List<Float> h = new ArrayList<>();
        h.add(delta);

        adjustHeight(coord, h);
    }
gets an interpolated value at the specified point
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainQuad.java