code: String nameFromDescType(String descType) {
          Matcher matcher = descTypePattern.matcher(descType);
          if (matcher.matches()) {
              return matcher.group(1);
          } else {
              return null;
          }
      }
docs: Given a descriptor type, extracts and returns the class name from it, if any.
  These types are obtained from field descriptors (JVMS 4.3.2) and method
  descriptors (JVMS 4.3.3). They have one of the following forms:
  
  I        // or any other primitive, or V for void
  [I       // array of primitives, including multi-dimensional
  Lname;   // the named class
  [Lname;  // array whose component is the named class (also multi-d)
  
  This method extracts and returns the class name, or returns empty for primitives, void,
  or array of primitives.
  
  Returns nullable reference instead of Optional because downstream
  processing can throw checked exceptions.
  
  @param descType the type from a descriptor
  @return the extracted class name, or null