//原来写法
Map<String, WmSoDetail> upDetailMap = upWmSoDetailList.stream().collect(Collectors.toMap(WmSoDetail::getStatus, item -> item));

//正确写法

Map<String, WmSoDetail> upDetailMap = upWmSoDetailList.stream().collect(Collectors.toMap(WmSoDetail::getStatus, item -> item,(k1, k2) -> k1));