为什么500错误返回json消息值为空

Spring boot应用程序有一个如下方法

getBasicInfoList(@RequestParam int pageNum, @RequestParam @Max(20)int pageSize)

pageSize不能超过20,如果超过20,则返回以下值

{
  "timestamp": 1602562522208,
  "status": 500,
  "error": "Internal Server Error",
  "message": "",
  "path": "/convertibleBond/basicInfos"
}

应用程序抛出以下异常

javax.validation.ConstraintViolationException: getBasicInfoList.pageSize: must be less than or equal to 20
    at org.springframework.validation.beanvalidation.MethodValidationInterceptor.invoke(MethodValidationInterceptor.java:117) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.6.RELEASE.jar:5.2.6.RELEASE]

那么为什么 message 值为空?如何让它成为现实 getBasicInfoList.pageSize: must be less than or equal to 20 ?