Obtengo el error a continuación después de ejecutar mi código java. Parece que hay un problema con el archivo XML solamente. Por lo tanto, no publiqué el código de Java. El código XML se da después del error. Lo copié de mi libro tal como está y, sin embargo, provoca un error. ¿Cómo puedo rectificar este error xml molesto?

"Some value of time" org.hibernate.cfg.annotations.Version <clinit>
INFO: Hibernate Annotations 3.3.1.GA
[main] INFO org.hibernate.cfg.Environment - Hibernate 3.3.2.GA
[main] INFO org.hibernate.cfg.Environment - hibernate.properties not found
[main] INFO org.hibernate.cfg.Environment - Bytecode provider name : javassist
[main] INFO org.hibernate.cfg.Environment - using JDK 1.4 java.sql.Timestamp handling
[main] INFO org.hibernate.cfg.Configuration - configuring from resource:     
/hibernate.cfg.xml
[main] INFO org.hibernate.cfg.Configuration - Configuration resource:     
 /hibernate.cfg.xml
[main] ERROR org.hibernate.util.XMLHelper - Error parsing XML:     
/hibernate.cfg.xml(3)     
The markup in the document preceding the root element must be well-formed.
Exception in thread "main" org.hibernate.HibernateException: Could not parse     
configuration: /hibernate.cfg.xml
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1542)
at org.hibernate.cfg.AnnotationConfiguration.doConfigure
    (AnnotationConfiguration.java:990)
at org.hibernate.cfg.AnnotationConfiguration.doConfigure
    (AnnotationConfiguration.java:69)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1476)
at org.hibernate.cfg.AnnotationConfiguration.configure
    (AnnotationConfiguration.java:972)
at org.hibernate.cfg.AnnotationConfiguration.configure
    (AnnotationConfiguration.java:69)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1462)
at org.hibernate.cfg.AnnotationConfiguration.configure
    (AnnotationConfiguration.java:966)
at com.examscam.model.User.persist(User.java:47)
at com.examscam.model.User.main(User.java:57)
    Caused by: org.dom4j.DocumentException: Error on line 3 of document  : The markup  
    in the document preceding the root element must be well-formed. Nested exception:
    The markup in the document preceding the root element must be well-formed.
at org.dom4j.io.SAXReader.read(SAXReader.java:482)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1532)
... 9 more

El archivo XML es el siguiente:

<?xml version = '1.0' encoding='UTF-8' ?>

<!Doctype hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

<property name = "connection.url">
jdbc:mysql://localhost/examscam
</property>

<property name = "connection.username">
root
</property>

<property name = "connection.password">
password
</property>

<property name = "connection.driver_class">
com.mysql.jdbc.Driver
</property>

<property name = "dialect">
org.hibernate.dialect.MySQLDialect
</property>

<property name = "transaction.factory_class">
org.hibernate.transaction.JDBCTransactionFactory
</property>

<property name = "current_session_context_class">
thread
</property>

<property name = "hibernate.show_sql">
true
</property>

</session-factory>
</hibernate-configuration>

EDITAR

org.hibernate.cfg.annotations.Version <clinit>
INFO: Hibernate Annotations 3.3.1.GA
[main] INFO org.hibernate.cfg.Environment - Hibernate 3.3.2.GA
[main] INFO org.hibernate.cfg.Environment - hibernate.properties not found
[main] INFO org.hibernate.cfg.Environment - Bytecode provider name : javassist
[main] INFO org.hibernate.cfg.Environment - using JDK 1.4 java.sql.Timestamp handling
[main] INFO org.hibernate.cfg.Configuration - configuring from resource:
 /hibernate.cfg.xml
[main] INFO org.hibernate.cfg.Configuration - Configuration resource: 
/hibernate.cfg.xml
[main] INFO org.hibernate.cfg.Configuration - Reading mappings from resource : 
com/xx  /portal/db/User.hbm.xml
Exception in thread "main" org.hibernate.MappingNotFoundException: resource: com/xx
/portal/db/User.hbm.xml not found
at org.hibernate.cfg.Configuration.addResource(Configuration.java:610)
at org.hibernate.cfg.AnnotationConfiguration.addResource
(AnnotationConfiguration.java:912)
at org.hibernate.cfg.AnnotationConfiguration.parseMappingElement
(AnnotationConfiguration.java:617)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1603)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1582)
at org.hibernate.cfg.AnnotationConfiguration.doConfigure
(AnnotationConfiguration.java:1002)
at    org.hibernate.cfg.AnnotationConfiguration.doConfigure
(AnnotationConfiguration.java:69)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1556)
at org.hibernate.cfg.AnnotationConfiguration.doConfigure
(AnnotationConfiguration.java:990)
at org.hibernate.cfg.AnnotationConfiguration.doConfigure
(AnnotationConfiguration.java:69)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1476)
at org.hibernate.cfg.AnnotationConfiguration.configure
(AnnotationConfiguration.java:972)
at org.hibernate.cfg.AnnotationConfiguration.configure
(AnnotationConfiguration.java:69)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1462)
at org.hibernate.cfg.AnnotationConfiguration.configure
(AnnotationConfiguration.java:966)
at com.examscam.model.User.persist(User.java:45)
at com.examscam.model.User.main(User.java:55)