code: public static Set<String> postQuery(String xml)
  			throws IOException{
  
  		//System.out.println(xml);
  
  
  		URL u = new URL(SERVICELOCATION);
  
  
  		String encodedXML = URLEncoder.encode(xml,"UTF-8");
  
  
  		InputStream in =  doPOST(u,encodedXML);
  
  		Set<String> pdbIds = new TreeSet<String>();
  
  
  		try (BufferedReader rd = new BufferedReader(new InputStreamReader(in))) {
  
  			String line;
  			while ((line = rd.readLine()) != null) {
  
  				pdbIds.add(line);
  
  			}
  			rd.close();
  		}
  
  
  		return pdbIds;
  
  
  
  	}
docs: post am XML query (PDB XML query format)  to the RESTful RCSB web service
  
  @param xml
  @return a list of PDB ids.