code: public void setConfigurations(Collection<? extends Configuration> configurations) {
  		Assert.notNull(configurations, "Configurations must not be null");
  		this.configurations = new ArrayList<>(configurations);
  	}
docs: Sets Jetty {@link Configuration}s that will be applied to the {@link WebAppContext}
  before the server is created. Calling this method will replace any existing
  configurations.
  @param configurations the Jetty configurations to apply