JAVA - Create an instance of an object of a class?

So,

I have a class called "GeraForm" that I need it to return a string in the HTML style form with some information contained in a note. I got the code to work when I pass a particular class to it, but I'd like the code, before returning the String, to create an instance of an object of the class so that, there, I could read the annotations of the methods of that class object and generate HTML form.

What happens is that when I get the value of the fields in the annotation, for example

String label = annotation.label(); 

I'm getting a nullPointerException, which I believe is due to the lack of an object.

My annotation Campo.java :

import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.lang.annotation.ElementType;
import java.lang.annotation.RetentionPolicy;

@Target( { ElementType.METHOD } )
@Retention( RetentionPolicy.RUNTIME )
public @interface Campo {

    int maxLength() default 0;

    boolean required() default false;

    String label();

}

My class GeraForm.Java :

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class GeraForm {

    public String incluir(Class<?> formClass) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        Class<?> wantedClass = formClass;
        Method[] classMethods = wantedClass.getDeclaredMethods();
        String methodName = "temp";

        //I need to return a String in HTML form style at the and of the method
        //Im gonna construct the string piece by piece to return at the end of the method
        String returnString = "a";

        //I get the name of the method and put it to lower case
        for(int i=0; i < classMethods.length; i++) {
            if(classMethods[i].getName().startsWith("set")) {
                methodName = classMethods[i].getName().substring(3, classMethods[i].getName().length()).toLowerCase();
            }
        }

        Campo annotation = classMethods[0].getAnnotation(Campo.class);

        //Here I get the value of every field in the annotation
        String label = annotation.label(); 
        int maxLength = annotation.maxLength();
        boolean required = annotation.required();

        returnString = label+"<input type=\"text\" name=\""+methodName+"\"";
       if(maxLength != 0) {
           returnString = returnString +" maxlength=\""+maxLength+"\"";
       }
        if(required == true) {
            returnString = returnString + " required=\"" + required + "\"";
        }

        returnString = returnString + ">";


        return returnString;
    }

}