According to the Java spec and Class.getSuperclass(), interfaces don't have java.lang.Object as their super class.

Types.directSupertypes( TypeMirror of an interface ) incorrectly returns java.lang.Object as the direct super type.

------ Processor------
import java.util.*;
import javax.annotation.processing.*;
import javax.lang.model.element.*;
import javax.lang.model.type.*;
import javax.lang.model.util.*;
import static javax.lang.model.SourceVersion.*;
import static javax.lang.model.type.TypeKind.*;

@SupportedAnnotationTypes("*")
@SupportedSourceVersion(RELEASE_7)
public class Processor extends AbstractProcessor {
    public void init(ProcessingEnvironment penv) {
        super.init(penv);
    }
    public boolean process(Set<? extends TypeElement> typeElementSet,
            RoundEnvironment renv) {
        for ( TypeElement typeElement : typeElementSet )
        {
          Set<? extends Element> elements = renv.getElementsAnnotatedWith( typeElement );
          for ( Element element : elements )
          {
            TypeMirror type = element.asType();
            System.out.println( "Type: " + type.toString() );
            List<? extends TypeMirror> supers = processingEnv.getTypeUtils().directSupertypes( type );

            for ( TypeMirror superClass : supers )
              System.out.println( "Super class: " + superClass.toString() );
          }
        }
        return true ;
    }
}
-------------- Interface ---
@SuppressWarnings("all")
class Interface1 {}
--------------------
javac -classpath . Processor.java
javac -classpath . -processor Processor Interface1.java

Will print:
Type: Interface1
Super class: java.lang.Object