java输入流问题

我有好几个方法每个里面都用到了sc.write(s);这个写入的方法，我在主函数里调用这些方法，结果报出：
Exception in thread "main" org.apache.poi.openxml4j.exceptions.OpenXML4JRuntimeException: Fail to save: an error occurs while saving the package : The part /docProps/app.xml fail to be saved in the stream with marshaller org.apache.poi.openxml4j.opc.internal.marshallers.DefaultMarshaller@4fbf1942

at org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:503)
at org.apache.poi.openxml4j.opc.OPCPackage.save(OPCPackage.java:1467)
at org.apache.poi.POIXMLDocument.write(POIXMLDocument.java:217)
at test.UseProcess.UseProcessSum(UseProcess.java:198)
at test.TestMain.main(TestMain.java:42)
Caused by: org.apache.poi.openxml4j.exceptions.OpenXML4JException: The part /docProps/app.xml fail to be saved in the stream with marshaller org.apache.poi.openxml4j.opc.internal.marshallers.DefaultMarshaller@4fbf1942
at org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:494)
... 4 more

我只执行一个方法就没事，我该怎么办啊？