docs: String getClassName(String name) {
          char[] s = new char[name.length()+1];
          char c;
          int j = 0;
  
          if (!Character.isJavaIdentifierStart(name.charAt(0))) {
              s[j++] = '_';
          }
          for (int i=0; i < name.length(); i++, j++) {
              c = name.charAt(i);
              if ( Character.isJavaIdentifierPart(c) ) {
                  s[j] = c;
              } else {
                  s[j] = '_';
              }
          }
          return (new String(s)).trim();
       }