private void validateKeys( PackageMaterialProperties configDefinedByPlugin, PackageMaterialProperties configProvidedByUser, ValidationResultMessage validationResultMessage) { List<String> invalidKeys = new ArrayList<String>(); for (String key : configProvidedByUser.keys()) { if (!configDefinedByPlugin.hasKey(key)) { invalidKeys.add(key); } } if (!invalidKeys.isEmpty()) { validationResultMessage.addError( create( String.format( "Unsupported key(s) found : %s. Allowed key(s) are : %s", join(invalidKeys), join(configDefinedByPlugin.keys())))); } }