@Override
    public boolean exists() {
        URL url;
        if (this.clazz != null) {
            url = this.clazz.getResource(this.path);
        } else {
            url = this.classLoader.getResource(this.path);
        }
        return (url != null);
    }
This implementation checks for the resolution of a resource URL.

@return if exists.
@see java.lang.ClassLoader#getResource(String)
@see java.lang.Class#getResource(String)
src/main/java/spark/resource/ClassPathResource.java