processor/src/main/java/com/hannesdorfmann/parcelableplease/processor/codegenerator/SupportedTypes.java
public static TypeMirror getWildcardType(String type, String elementType, Elements elements,
                                           Types types) {
    TypeElement arrayList = elements.getTypeElement(type);
    TypeMirror elType = elements.getTypeElement(elementType).asType();
    return types.getDeclaredType(arrayList, types.getWildcardType(elType, null));
  }
public static TypeMirror getWildcardType(String type, String elementType, Elements elements,
                                           Types types) {
    TypeElement arrayList = elements.getTypeElement(type);
    TypeMirror elType = elements.getTypeElement(elementType).asType();
    return types.getDeclaredType(arrayList, types.getWildcardType(elType, null));
  }
Get the wildcardType