有人可以帮助做什么来解决以下提到的异常时，存根下面提到的行

Mockito.doNothing().when(customerRepository.save(customerProduct))

建议我在这里正确执行

E.g. thenReturn() may be missing.

正确的短截线示例：

when(mock.isOk()).thenReturn(true);
    when(mock.isOk()).thenThrow(exception);
    doThrow(exception).when(mock).someVoidMethod();

提示：

1. missing thenReturn()
 2. you are trying to stub a final method, which is not supported
 3. you are stubbing the behaviour of another mock inside before 'thenReturn' instruction is completed