问题 @ControllerAdvice异常处理程序方法未被调用

我有以下控制器类

package com.java.rest.controllers;
@Controller
@RequestMapping("/api")
public class TestController {

@Autowired
private VoucherService voucherService;


@RequestMapping(value = "/redeemedVoucher", method = { RequestMethod.GET })
@ResponseBody
public ResponseEntity redeemedVoucher(@RequestParam("voucherCode") String voucherCode) throws Exception {
    if(voucherCode.equals( "" )){
        throw new MethodArgumentNotValidException(null, null);
    }
    Voucher voucher=voucherService.findVoucherByVoucherCode( voucherCode );
    if(voucher!= null){
        HttpHeaders headers = new HttpHeaders();
        headers.add("Content-Type", "application/json; charset=utf-8");
        voucher.setStatus( "redeemed" );
        voucher.setAmount(new BigDecimal(0));
        voucherService.redeemedVoucher(voucher);
        return new ResponseEntity(voucher, headers, HttpStatus.OK);

    }
    else{
        throw new ClassNotFoundException();
    }
};

}

对于异常处理，我使用Spring3.2建议处理程序如下

package com.java.rest.controllers;


@ControllerAdvice
public class VMSCenteralExceptionHandler extends ResponseEntityExceptionHandler{

@ExceptionHandler({
    MethodArgumentNotValidException.class
})
public ResponseEntity<String> handleValidationException( MethodArgumentNotValidException methodArgumentNotValidException ) {
    return new ResponseEntity<String>(HttpStatus.OK );
}

 @ExceptionHandler({ClassNotFoundException.class})
        protected ResponseEntity<Object> handleNotFound(ClassNotFoundException ex, WebRequest request) {
            String bodyOfResponse = "This Voucher is not found";
            return handleExceptionInternal(null, bodyOfResponse,
              new HttpHeaders(), HttpStatus.NOT_FOUND , request);
        }

}

我已将XML bean定义定义为

<context:component-scan base-package="com.java.rest" />

从控制器抛出的异常不由控制器通知处理程序处理。我用谷歌搜索了几个小时，但找不到任何参考为什么会发生这种情况。 我跟着描述了 http://www.baeldung.com/2013/01/31/exception-handling-for-rest-with-spring-3-2/ 这里。

如果有人知道请告诉我为什么处理程序不处理异常。