code: public static boolean isValidJavaClassName(String className) {
  
          if (CmsStringUtil.isEmpty(className)) {
              return false;
          }
          int length = className.length();
          boolean nodot = true;
          for (int i = 0; i < length; i++) {
              char ch = className.charAt(i);
              if (nodot) {
                  if (ch == '.') {
                      return false;
                  } else if (Character.isJavaIdentifierStart(ch)) {
                      nodot = false;
                  } else {
                      return false;
                  }
              } else {
                  if (ch == '.') {
                      nodot = true;
                  } else if (Character.isJavaIdentifierPart(ch)) {
                      nodot = false;
                  } else {
                      return false;
                  }
              }
          }
          return true;
      }
docs: Checks if the given class name is a valid Java class name.<p>
  
  <b>Directly exposed for JSP EL</b>, not through {@link org.opencms.jsp.util.CmsJspElFunctions}.<p>
  
  @param className the name to check
  
  @return true if the given class name is a valid Java class name