Warning: validation was turned on but an org.xml.sax.ErrorHandler...

Question

Any idea why this error is happening and how to fix it? I'm getting this error when trying to parse/load a config file:

Error

Warning: validation was turned on but an org.xml.sax.ErrorHandler was not
set, which is probably not what is desired.  Parser will use a default
ErrorHandler to print the first 10 errors.  Please call
the 'setErrorHandler' method to fix this.
Error: URI=null Line=3: Document root element "persistence", must match DOCTYPE root "null".
Error: URI=null Line=3: Document is invalid: no grammar found.
null
[]
null

Main code

public static void main(String[] args) throws ConfigurationException {
     config = new XMLPropertiesConfiguration(new File("META-INF/vamola.xml"));                                 
     System.out.println(config.getString("persitence-unit.provider"));
     System.out.println(config.getList("persistence-unit.properties.name"));

    }

XML FILE

<?xml version="1.0"?>
<persistence version="1.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"&gt;
    <persistence-unit name="dbBank" transaction-type="RESOURCE_LOCAL">
     <provider>oracle.toplink.essentials.PersistenceProvider</provider>

     <class>br.ufg.inf.server.Account</class>
     <class>br.ufg.inf.server.UserBank</class>

     <properties>
      <property name="toplink.jdbc.user" value="derby" />
      <property name="toplink.jdbc.password" value="senha" />
      <property name="toplink.jdbc.url" value="jdbc:derby://192.168.80.125:1527/db/master/dbBank;create=true"/>
      <property name="toplink.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver" />
      <property name="toplink.ddl-generation" value="create-tables" />
      <property name="toplink.logging.level" value="OFF" />
      <property name="toplink.target-database" value="Derby" />
     </properties>
    </persistence-unit>
</persistence>

Answer 1

If your parsing an XML document with validation turned on, you need to specify either a DTD or an XML schema in a DOCTYPE at the start of your XML document. Your parser is basically complaining that it doesn't know how to validate your document because no grammer has been specified to validate the mark up.

You already have an XML schema, so you probably want:

<!DOCTYPE schema PUBLIC "http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"&gt;

If you want to turn off validation, you need something like:

spf.setValidating(false); (Where spf is a SaxParserFactory)

Answer 2

The XML document defines the default namespace http://java.sun.com/xml/ns/persistence and includes a url, where the schema can be found (xsi:schemaLocation attribute, first value is the namespace, second the url or path).

Please double-check if this url is accessible at the time you parse it. An alternative is to download the schema, put it on the file system and modify the xsi:schemaLocation value.

Answer 3

The exception says that an ErrorHandler wasn't set. This means that the parser uses its built-in error handler, which simply writes messages to the console. If you actually want to validate, you need to create an ErrorHandler implementation and attach it to the DocumentBuilder.

For more information, read this: http://www.kdgregory.com/index.php?page=xml.parsing (error handlers are about 1/3 of the way down).

Or, as other responses have suggested, you can just turn validation off.