code: public ClassInfoList getClassesWithMethodParameterAnnotation(final String methodParameterAnnotationName) {
          if (closed.get()) {
              throw new IllegalArgumentException("Cannot use a ScanResult after it has been closed");
          }
          if (!scanSpec.enableClassInfo || !scanSpec.enableMethodInfo || !scanSpec.enableAnnotationInfo) {
              throw new IllegalArgumentException("Please call ClassGraph#enableClassInfo(), #enableMethodInfo(), "
                      + "and #enableAnnotationInfo() before #scan()");
          }
          final ClassInfo classInfo = classNameToClassInfo.get(methodParameterAnnotationName);
          return classInfo == null ? ClassInfoList.EMPTY_LIST : classInfo.getClassesWithMethodParameterAnnotation();
      }
docs: Get classes that have a method with a parameter that is annotated with an annotation of the named type.
  
  @param methodParameterAnnotationName
  the name of the method parameter annotation.
  @return A list of classes that have a method with a parameter annotated with the named annotation type, or
  the empty list if none.