ZipInputStream zIn =  new  ZipInputStream(userForm.getMyFile().getInputStream());
ZipEntry zEn;
( 1 )  while  ((zEn = zIn.getNextEntry()) !=  null )
{
  DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
  DocumentBuilder db=dbf.newDocumentBuilder();
  Document xmldoc=db.parse(zIn);
  msg+=xmldoc.getFirstChild().getNodeName()+" ";
}

...
InputSource is= new  InputSource(b);
DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
DocumentBuilder db=dbf.newDocumentBuilder();
Document xmldoc=db.parse(is);
...