docs: protected synchronized Expression getParsedExpression() {
          if (parsedExpression == null) {
              try {
                  parsedExpression = EXPRESSION_PARSER.parseExpression(getExpression());
              }
              catch (ParseException e) {
                  throw new IllegalArgumentException("[" + getExpression() + "] is not a valid SpEL expression", e);
              }
          }
          return parsedExpression;
      }