Create file inside folder "resources" of spring project

Question

In my current spring, some forms have a field where the user can upload a file, which should be saves inside the folder resources from project (src/main/resources, following the structure created by maven).

the method responsible for save the file in this folder is working ok until this line:

URL path = this.getClass().getClassLoader().getResource(file);

the variable path is staying with the value null. the variable file is defined with this value:

String file = "/"+this.getName()+"/"+String.valueOf(id)+"/picture.jpg";

Anyone can tell me the right way to do this?

PS.: the complete code for this method is:

public boolean upload_picture(E e, MultipartFile f) {
    Integer id = null;

    if(f == null) {
        return false;
    }

    Class<?> clazz = e.getClass();
    Method methods[] = clazz.getDeclaredMethods();
    for(int i=0; i<methods.length; i++) {
        if(methods[i].getName().equals("getId")) {
            try {
                id = (Integer) methods[i].invoke(e);
            } catch (IllegalAccessException e1) {
                e1.printStackTrace();
                return false;
            } catch (IllegalArgumentException e1) {
                e1.printStackTrace();
                return false;
            } catch (InvocationTargetException e1) {
                e1.printStackTrace();
                return false;
            }
        }
    }

    BufferedImage src;
    try {
        src = ImageIO.read(new ByteArrayInputStream(f.getBytes()));
    } catch (IOException e3) {
        e3.printStackTrace();
        return false;
    }

    String file = "/"+this.getName()+"/"+String.valueOf(id)+"/picture.jpg";
    URL path = this.getClass().getClassLoader().getResource(file);
    File destination;
    try {
        destination = new File(path.toURI());
    } catch (URISyntaxException e2) {
        destination = new File(path.getPath());
        e2.printStackTrace();
    }

    try {
        ImageIO.write(src, "jpeg", destination);
        return true;
    } catch (IOException e1) {
        e1.printStackTrace();
        return false;
    }
}