Using JAVA to parse an XML document

[Tavia Young]

Hi All,
I am currently working on parsing an XML document such that Java objects could be created and stored in the database. I chose to use SAX since I will only be reading the data, creating the objects and populating the DB.
A NullPointerException,
java.lang.NullPointerException
at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:658)
at org.apache.crimson.parser.Parser2.parse(Parser2.java:333)
at org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:448)
is generated with the following lines of code:
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser parser = spf.newSAXParser();
XMLReader reader = parser.getXMLReader();
reader.setContentHandler(this);
reader.parse(new InputSource("file:///C|/temp/temp.xml"));
Is the error occuring a result of not being able to locate the file? Is there something missing on the classpath (currently using JDK 1.4)?
Thanks in advance for your help!

[Nathaniel Stoddard]

Typically, if a file isn't found a more descriptive exception will be thrown. You're going to have to debug this, or at least find out which object is null when it shouldn't be.
It's possible you haven't configured an XML parser like Xerces on your computer, or having included it in your classpath, so your factory in turn returns null when you ask for a SAX parser.
You can step through it in your debugger to find out. Or more likely the stack trace will print out the line where the null pointer exception was thrown.

[Lasse Koskela]

Since you're using JDK1.4 (and the stack trace is already coming from org.apache.crimson...), the classpath shouldn't be a problem. My first guess would be that

Originally posted by Tavia Young:
reader.parse(new InputSource("file:///C|/temp/temp.xml"));

has a malformed file path/URL. You should try using a bit different syntax or simply use another constructor for InputSource -- e.g. the one which takes a (File)InputStream.

[Tavia Young]

Thanks very much, Nathaniel and Lasse. I installed Xerces and all is well now. However, I will also try Lasse's suggestion. Thanks again! =)