With relation to [SPR-11126] problem converting empty parameter to List,

We want to get a request parameter with the type of List<String> in the Spring-mvc Controller class like below

SampleController.java
@RequestMapping(value = "/urlpath")
public void create(@RequestParam(value = "param") List<String> paramList) {
 ...
}

When invoking ".../urlpath?param=", We expect List<String> has size 1 with empty String value, but actually the size of List<String> is 0.

Actually StringUtils.commaDelimitedListToStringArray(String) method is a real worker, but the purpose of that method is to return the empty array in case of empty input(by java doc).
So, I slightly chnaged convert(Object source, TypeDescriptor sourceType,
TypeDescriptor targetType) method in the StringToCollectionConverter
class.

reated Issue: SPR-11126