Compile and run following

---%<---
package mustangtest;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.xml.sax.InputSource;

public class CDataTest {
    
    private static final String TEST = "<?xml version=\"1.0\"?>\n"+
            "<value>\n"+
            "<![CDATA[//IfStatement/Statement/Block[count(*) = 0]]]>\n"+
            "</value>\n";
    
    /** Creates a new instance of CDataTest */
    public CDataTest() {
    }
    
    public static void main(String [] args) {
        System.out.println("Java version "+System.getProperty("java.version"));
        DocumentBuilder db;
        try {
            db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            db.parse(new InputSource(new StringReader(TEST)));
            System.out.println("parsed.");
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
    
}
---%<---

Under JDK 1.5.0 and most of mustang builds it works. With JDK1.6-b49 it produces:

---%<---
Java version 1.6.0-ea
[Fatal Error] :4:10: XML document structures must start and end within the same entity.
org.xml.sax.SAXParseException: XML document structures must start and end within the same entity.
        at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:280)
        at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292)
        at mustangtest.CDataTest.main(CDataTest.java:23)
---%<---

The problem is the end of CDATA section. If the last character is not left angle bracket it passes but ']]]>' sequence is not recognized as a bracket and end of CDATA.