code: public static String getCaller() {
          StackTraceElement[] stacks = Thread.currentThread().getStackTrace();
          if (stacks != null) {
              for (int i = 0; i < stacks.length; i++) {
                  String cn = stacks[i].getClassName();
                  if (cn != null && !Constants.CLASSNAME_TO_ESCAPE.contains(cn)) {
                      return cn;
                  }
              }
          }
          return null;
      }
docs: Extracts the tag from the current stack trace.
  
  @return the qualified name of the first non escaped class on the stack.