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I am getting null pointer exception when i get the data from xml document using web service

String name= "Nsss";
String resulturl ="http://ssss/res/get?sid="+name+"";
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(resulturl));
Document doc = db.parse(resulturl);
System.out.println("sssssssssssssssssssssssssssssssssssssssssssssssssss"+doc.getDoctype().getTextContent());
I am getting this exception.
java.lang.NullPointerException
at com.controller.StudentsResultsController.main(ResultsController.java:130)

You should check to see what the resulturl variable is before you use it, but the other thing you need to address is: You are not using the InputSource at all. The following is likely to work better than what you have:
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(resulturl));
Document doc = db.parse(is);
EDIT
The Fatal Error is caused by the following:
StringReader(resulturl) takes a string argument that must be XML, not a filename or a URL. The parser is reading the value of the string variable, resulturl, and failing immediately because an XML document may not begin with an h character.
Try changing the above to:
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(new InputSource(resulturl));

How to Read/Write to an xml file?

I have an xml file already created that has tags and values for the tags.
<?xml version="1.0" encoding="utf-16"?>
<Scoreboard>
<Score>
<username>Ryan</username>
<points>200</points>
</Score>
All I want to be able to do is read the information within the tags as well as write tot he already created xml document with a new tag. If i wanted to add username: Andrew, points: 100, how would i accomplish this? In addition how could i read the xml file so that i could display all the scores and its information?
Read - InputStream is = getAssets().open("highscores2.xml");
DocumentBuilderFactory dbFactory =
DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(is);
Element element = doc.getDocumentElement();
element.normalize();
write - InputStream is = getAssets().open("highscores2.xml");
DocumentBuilderFactory dbFactory =
DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(is);
NodeList nodes = doc.getElementsByTagName("Score");
Text a = doc.createTextNode("Dylly");
Element p = doc.createElement("username");
p.appendChild(a);
nodes.item(0).getParentNode().insertBefore(p, nodes.item(0));
As of right now I have my xml file stored in an asset folder but when i try to write to it I am given an error - saying it is read only. How can I get around this as well?
Any help would be greatly appreciated, I have spent all afternoon trying to find a solution to this problem and have come up with almost nothing, thanks.

There's a class for writing an xml file:
serializer = Xml.newSerializer();
writer = new StringWriter();
try {
serializer.setOutput(writer);
serializer.startDocument("UTF-8", true);
serializer.setPrefix(prefix, namespace);
serializer.startTag(prefix, tagName);
serializer.attribute(prefix, attrName, value);
serializer.endTag(prefix, tagName);
serializer.endDocument();
return writer.toString();
} catch (IOException e) {
throw new RuntimeException(e);
}
And even for reading an xml file:
XmlPullParserFactory xmlPullParserFactory = XmlPullParserFactory.newInstance();
xmlPullParserFactory.setNamespaceAware(true);
XmlPullParser xmlPullParser = xmlPullParserFactory.newPullParser();
xmlPullParser.setInput(new StringReader(xml));
return xmlPullParser;

Unable to read an uploaded multipart xml file

I am trying to write a service that receives a xml file and parses it and does some additional processing.
At the UI controller I converted the multipart file contents to a string and passed it to the service.
From the UI controller - I upload the file and call the service method to parse the xml file
MultipartFile newFile=multiPartRequest.getFile("newFileUpload");
String fileContent = new String(newFile.getBytes());
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
InputSource is = new InputSource(new StringReader(fileContent));
doc = dBuilder.parse(is);
However, doc is always null. What is the best way for me to rest this xml file?

I think its a problem with the
String fileContent String fileContent = new String(newFile.getBytes());
Since not all the bytes of the file are just text , you have the header and eof and bytes that don't represent a text .
What you should do is make a InputStream and build the document off that , like so :
try{
MultipartFile newFile=multiPartRequest.getFile("newFileUpload");
InputStream is = new newFile.getInputStream();
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(is);
} catch (SAXException | IOException | ParserConfigurationException ex) {
Logger.getLogger(JavaApplication4.class.getName()).log(Level.SEVERE, null, ex);
}

Create a DOM Document from an Url

the url : http://www.evemarketeer.com/api/orders/10000043/30119/xml
I tried this
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(url.openStream());
But isn't working, anyone got any idea to create a Document with an easy method ?
Thx

This works for me (returns 28 "row" elements)
URL url = new URL("http://www.evemarketeer.com/api/orders/10000043/30119/xml");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(url.openStream());
NodeList nodes = doc.getElementsByTagName("row");
System.out.println(nodes.getLength() + " nodes found");

String as Document

I'm following this turorial on parsing XML with XPath, and it gives the following example to open a document:
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true); // never forget this!
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("books.xml");
What I would like to do, is change that so that the Document is reading a String variable that I already have made, instead of reading from a file. How can I do that?

builder.parse(new InputSource(new StringReader("<some><xml></xml></some>")));

Look here
DocumentBuilderFactory dbf =
DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(xmlRecords));
Document doc = db.parse(is);

You may try this one:
public static Document stringToDom(String xmlSource)
throws SAXException, ParserConfigurationException, IOException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
return builder.parse(new InputSource(new StringReader(xmlSource)));
}