I use hebern8IDE throws Exception when I clicked "Apply" button,I do not know why???

Exception lists :

E:\hibern8ide-0.9>java -classpath E:\hibern8ide-0.9\lib\pf-joi-full.jar;E:\hiber
n8ide-0.9\lib\hibernate2.jar;E:\hibern8ide-0.9\lib\hibern8ide.jar;E:\hibern8ide-
0.9\lib\cglib2.jar;E:\hibern8ide-0.9\lib\commons-collections.jar;E:\hibern8ide-0
.9\lib\commons-lang.jar;E:\hibern8ide-0.9\lib\commons-logging.jar;E:\hibern8ide-
0.9\lib\dom4j.jar;E:\hibern8ide-0.9\lib\log4j.jar;E:\hibern8ide-0.9\lib\odmg.jar
;E:\hibern8ide-0.9\lib\xalan.jar;E:\hibern8ide-0.9\lib\jdbc2_0-stdext.jar;E:\hib
ern8ide-0.9\lib\jta.jar;E:\hibernateTest\src\;E:\hibernateTest\WEB-INF\classes\
net.sf.hibern8ide.Hibern8IDE
18:32:28,452 INFO Environment:432 - Hibernate 2.1.1
18:32:28,472 INFO Environment:466 - loaded properties from resource hibernate.p
roperties: {hibernate.connection.driver_class=oracle.jdbc.driver.OracleDriver, h
ibernate.cglib.use_reflection_optimizer=true, hibernate.cache.provider_class=net
.sf.hibernate.cache.HashtableCacheProvider, hibernate.max_fetch_depth=1, hiberna
te.dialect=net.sf.hibernate.dialect.Oracle9Dialect, hibernate.jdbc.use_streams_f
or_binary=true, hibernate.jdbc.batch_size=0, hibernate.query.substitutions=true
1, false 0, yes 'Y', no 'N', hibernate.proxool.pool_alias=pool1, hibernate.conne
ction.username=qdjs, hibernate.connection.url=jdbc:oracle:thin:@135.163.64.223:1
521:crm, hibernate.show_sql=true, hibernate.connection.password=qdjs, hibernate.
connection.pool_size=1}
18:32:28,472 INFO Environment:480 - using java.io streams to persist binary typ
es
18:32:28,472 INFO Environment:481 - using CGLIB reflection optimizer
18:32:28,492 INFO Configuration:877 - configuring from file: hibernate.cfg.xml
18:32:28,722 INFO Configuration:300 - Mapping resource: testcom/util/Cat.hbm.xm
l
18:32:28,942 INFO Binder:225 - Mapping class: testcom.util.Cat -> CAT
18:32:29,243 INFO Configuration:300 - Mapping resource: testcom/util/Customer.h
bm.xml
18:32:29,343 INFO Binder:225 - Mapping class: testcom.util.Customer -> DC_CUSTO
MER
18:32:29,723 INFO Configuration:998 - Configured SessionFactory: null
18:32:29,723 INFO Configuration:166 - Mapping file: E:\hibernateTest\src\testco
m\util\Cat.hbm.xml
18:32:29,763 ERROR Configuration:250 - Could not compile the mapping document
net.sf.hibernate.MappingException: duplicate import: Cat
at net.sf.hibernate.cfg.Mappings.addImport(Mappings.java:82)
at net.sf.hibernate.cfg.Binder.bindClass(Binder.java:126)
at net.sf.hibernate.cfg.Binder.bindRootClass(Binder.java:217)
at net.sf.hibernate.cfg.Binder.bindRoot(Binder.java:1204)
at net.sf.hibernate.cfg.Configuration.add(Configuration.java:247)
at net.sf.hibernate.cfg.Configuration.addFile(Configuration.java:169)
at net.sf.hibern8ide.Hibern8IDE.reconfig(Hibern8IDE.java:137)
at net.sf.hibern8ide.Hibern8IDE$3.configurationChanged(Hibern8IDE.java:3
83)
at net.sf.hibern8ide.ConfigurationUI$ApplyConfig.actionPerformed(Configu
rationUI.java:245)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:17
86)

Cat.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
<class name="testcom.util.Cat" table="CAT">
<id name="id" type="string">
<column name="CAT_ID" not-null="true" sql-type="char(32)"/>
<generator class="sequence"/>
</id>
<property name="name">
<column name="NAME" not-null="true" sql-type="varchar(16)"/>
</property>
<property name="sex"/>
<property name="weight"/>
</class>
</hibernate-mapping>

Cat.java
package testcom.util;

/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Date: 2004-5-13 </p>
* <p>Time: 16:53:15 </p>
* <p>Copyright: Copyright (c) 2004</p>
*/
public class Cat {

private String id;
private String name;
private char sex;
private float weight;

public Cat() {
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public char getSex() {
return sex;
}

public void setSex(char sex) {
this.sex = sex;
}

public float getWeight() {
return weight;
}

public void setWeight(float weight) {
this.weight = weight;
}

}

Hi

I try to use hibernate, but I always get following error (some error with the DTD sheme) when I try to configure hibernate:

Configuration cfg = new Configuration().configure ("/resources/hibernate.cfg.xml");

->
0 [main] INFO net.sf.hibernate.cfg.Environment - Hibernate 2.1.1
0 [main] INFO net.sf.hibernate.cfg.Environment - hibernate.properties not found
0 [main] INFO net.sf.hibernate.cfg.Environment - using CGLIB reflection optimizer
15 [main] INFO net.sf.hibernate.cfg.Configuration - configuring from resource: /resources/hibernate.cfg.xml
15 [main] INFO net.sf.hibernate.cfg.Configuration - Configuration resource: /resources/hibernate.cfg.xml
78 [main] DEBUG net.sf.hibernate.util.DTDEntityResolver - trying to locate http://hibernate.sourceforge.net/hibern ... on-2.0.dtd in classpath under net/sf/hibernate/
net.sf.hibernate.HibernateException: problem parsing configuration/resources/hibernate.cfg.xml
at net.sf.hibernate.cfg.Configuration.doConfigure(Configuration.java:906)
at net.sf.hibernate.cfg.Configuration.configure(Configuration.java:845)
at ch.ejpd.jdbkof.client.testClient.<init>(testClient.java:56)
at ch.ejpd.jdbkof.client.testClient.main(testClient.java:85)
Caused by: org.dom4j.DocumentException: Error on line 3 of document : java.lang.NullPointerException Nested exception: java.lang.NullPointerException
at org.dom4j.io.SAXReader.read(SAXReader.java:355)
at net.sf.hibernate.cfg.Configuration.doConfigure(Configuration.java:901)
... 3 more
78 [main] ERROR net.sf.hibernate.cfg.Configuration - problem parsing configuration/resources/hibernate.cfg.xml
org.dom4j.DocumentException: Error on line 3 of document : java.lang.NullPointerException Nested exception: java.lang.NullPointerException
at org.dom4j.io.SAXReader.read(SAXReader.java:355)
at net.sf.hibernate.cfg.Configuration.doConfigure(Configuration.java:901)
at net.sf.hibernate.cfg.Configuration.configure(Configuration.java:845)
at ch.ejpd.jdbkof.client.testClient.<init>(testClient.java:56)
at ch.ejpd.jdbkof.client.testClient.main(testClient.java:85)
Nested exception:
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)
at org.dom4j.io.SAXReader.read(SAXReader.java:339)
at net.sf.hibernate.cfg.Configuration.doConfigure(Configuration.java:901)
at net.sf.hibernate.cfg.Configuration.configure(Configuration.java:845)
at ch.ejpd.jdbkof.client.testClient.<init>(testClient.java:56)
at ch.ejpd.jdbkof.client.testClient.main(testClient.java:85)

My config doc:

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<hibernate-configuration>
<session-factory>

<!--Mapping files -->
<mapping resource="DTOSystemInfo.hbm.xml"/>
</session-factory>
</hibernate-configuration>

Whats wrong ... (I am using jdk 1.4.2_02 with eclipse, hibernate 2.1.3)

Thanks very much