How to validate an XML file against an XSD file?

Here's how to do it using Xerces2. A tutorial for this, here (req. signup).

Original attribution: blatantly copied from here:

import org.apache.xerces.parsers.DOMParser;
import java.io.File;
import org.w3c.dom.Document;

public class SchemaTest {
  public static void main (String args[]) {
      File docFile = new File("memory.xml");
      try {
        DOMParser parser = new DOMParser();
        parser.setFeature("http://xml.org/sax/features/validation", true);
        parser.setProperty(
             "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation", 
             "memory.xsd");
        ErrorChecker errors = new ErrorChecker();
        parser.setErrorHandler(errors);
        parser.parse("memory.xml");
     } catch (Exception e) {
        System.out.print("Problem parsing the file.");
     }
  }
}

Are you looking for a tool or a library?

As far as libraries goes, pretty much the de-facto standard is Xerces2 which has both C++ and Java versions.

Be fore warned though, it is a heavy weight solution. But then again, validating XML against XSD files is a rather heavy weight problem.

As for a tool to do this for you, XMLFox seems to be a decent freeware solution, but not having used it personally I can't say for sure.