static String decapitalizeNormally(String propertyName) {
    if (Strings.isNullOrEmpty(propertyName)) {
      return propertyName;
    }
    return Character.toLowerCase(propertyName.charAt(0)) + propertyName.substring(1);
  }
Returns the {@code propertyName} with its first character in lower case.
value/src/main/java/com/google/auto/value/processor/PropertyNames.java