javac is normally adding visibility bridges for methods if they are public but declared by a package-private class:

/* package-private */ class SuperClass {
  public Object foo() { return null; }
}
public class SubClass extends SuperClass { }

This is not the case if a method has a generic type:

/* package-private */ class SuperClass<X> {
  public X foo() { return null; }
}
public class SubClass extends SuperClass<Void> { }

As a result, reflective access of this method fails with an IllegalAccessException if the following code is run from outside the package of SuperClass and SubClass:

SubClass.class.getMethod("foo").invoke(new SubClass());

I would expect javac to create a visibility bridge for the method in question to allow for reflective access.