List遍歷出錯

List<object[]>報錯:java.lang.ClassCastException: java.util.HashMap cannot be

List<Map<String,Object>>

//{permission_parent=1, permission_name=新增新聞, permission_url=admin/index}
//{permission_parent=1, permission_name=修改新聞, permission_url=admin/index}
for (int i=0;i<session_object.size();i++){
   Map<String,Object>  map1= session_object.get(i);
   System.out.println(map1.get("permission_url"));
}