iBatis cannot return List or List ??

<param-map id="/le/queryForDocIdListParams">
       <property name="esubMainId" sqlType="BIGINT" validate="false" />
       <property name="esubExamId" sqlType="BIGINT" validate="false" />
    </param-map>
    <result-map id="/le/queryForDocIdListResults" class="java.lang.Long">
    </result-map>
    <map-sql id="/le/queryForDocIdList" type="query"
       param-map="/le/queryForDocIdListParams"
       result-map="/le/queryForDocIdListResults">
       <![CDATA[
              SELECT DOC_ID
              FROM LIC_LE_ESUB_SUPP_DOC
              WHERE  1=1
                    <isNotEmpty property="esubMainId">
                       AND LE_ESUB_MAIN_ID = ##esubMainId##
                    </isNotEmpty>
                      <isNotEmpty property="esubExamId">
                       AND LE_ESUB_EXAM_ID = ##esubExamId##
                    </isNotEmpty>
                    AND DELETE_IND = 'F'
       ]]>
    </map-sql>

Log:
java.lang.InstantiationException: java.lang.Long
at java.lang.Class.newInstance0(Class.java:335)
at java.lang.Class.newInstance(Class.java:303)

This caused by, there is no default constructor in java.lang.Long class, cannot initialize a Long with 'new Long()'.


Although java.lang.String has a default constructor, but there is no setter method to set result, so finally an arraylist contains several
empty string (""). Maybe I used it incorrectly.