public void setWindowSize(int width, int height) {
        putInteger("WindowWidth", width);
        putInteger("WindowHeight", height);
    }
Set the size of the window

@param width The width in pixels (default = width of the default framebuffer)
@param height The height in pixels (default = height of the default framebuffer)
jme3-core/src/main/java/com/jme3/system/AppSettings.java