JSP development error collection

【c:foreach】

Use index value instead of i, i.index should be used

<c:forEach items="${itemIndexList}" var="indexObj" varStatus="i">
    <td id="lastSum1${i.index}" class="alignright">
        <input id="a${i.index}" class="alignright" value="1" readonly="readonly" type="text">
    </td>
    </td>
</c:forEach>

i is in the form of an object, the following code will appear when output

<td+id%3D"ajavax.servlet.jsp.jstl.core.LoopTagSupport%241Status%4074047404"+class%3D"alignright">

【Null pointer】

List<Map<String,Object>> resultList = null;

This is wrong, the correct way is as follows

List<Map<String,Object>> resultList = new ArrayList<Map<String, Object>>();