Strange return for grid component

[滕训华]

I have a grid component in the page of T5 and its sources is got from
db.There is also another search field to filter the records.

 

I defined 2 method in my service class:

 

         List<CustomerInfo> getAllCustomers()

         List<CustomerInfo> search(String key)

 

when init this page will return all customers it run normally,but when I
input some to press the search button,it give me a error page:

 

An unexpected application exception has occurred.

Index: 4, Size: 4

 

I do not know why and how to slove this.please help .thanks.