Instantiate a Class annotated with some annotation

Question

I want to get information about fields from a Class on which a specific annotation is present by getting the annotation in annotation processor.

I can retrieve fully qualified class name from annotation but can't instantiate it, a ClassNotFoundException is being thrown, although class is there.

How can I check if class is not in class path or which classpath is included for annotation processor?

try {
                Class<?> clazz = Class.forName(((TypeElement) e).getQualifiedName().toString());
            } catch (ClassNotFoundException cnfe) {
                cnfe.printStackTrace();
            }

It returns class path for a class in my Android Application. — mallaudin, Jun 16 '17 at 15:09

score 2 · Accepted Answer · answered Jun 18 '17 at 12:56

What you're attempting to do in the code in the question is impossible because annotation processing occurs before the program is fully-compiled. That's why you work with e.g. TypeElement objects instead of Class, because the class is not-yet compiled.

On the other hand, if you just want to examine what sorts of fields are present, you can use the Element API for that, for example:

for (Element e : typeElement.getEnclosedElements()) {
    if (e.getKind() == ElementKind.FIELD) {
        VariableElement field = (VariableElement) e;
        //
    }
}

Instantiate a Class annotated with some annotation

1 Answers1