Hi,
I am new to hibernate and am experiencing an errot "org.hibernate.MappingException: Unknown entity:"trying to persist data. I have used import javax.persistence.Entity; and import javax.persistence.Id;. Kindly Help

Complete Error Log is
org.hibernate.MappingException: Unknown entity: com.org.ui.pc.shared.model.Contract
at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:1129)
at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1402)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:204)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:189)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:756)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:748)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:744)
at com.org.ui.pc.shared.model.TempMain.SaveContract(TempMain.java:43)
at com.org.ui.pc.shared.model.TempMain.main(TempMain.java:24)




The following is my hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<!-- a SessionFactory instance listed as /jndi/name -->
<session-factory name="java:hibernate/SessionFactory">
<!-- Database connection settings -->
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.url">jdbc:postgresql://localhost:5432/pcdb</property>
<property name="connection.username">postgres</property>
<property name="connection.password">Postgr*5</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>

<!-- Names the annotated entity class -->
<mapping class="com.org.ui.pc.shared.model.Contract"/>
</session-factory>

</hibernate-configuration>

My Bean is

package com.org.ui.pc.shared.model;

import java.sql.Timestamp;


import javax.persistence.Entity;
import javax.persistence.Id;

import com.extjs.gxt.ui.client.data.BaseTreeModel;
import com.extjs.gxt.ui.client.data.BeanModelTag;


@SuppressWarnings("serial")
@Entity
public class Contract extends BaseTreeModel implements BeanModelTag{

@Id
private String ContractId;

private Contract Parent;
private String ParentId;
private Contract Template;
private String TemplateId;
private String Version;
private String FinancialYear;
private String Cycle;
private String Status;
private String CreatedBy;
private Timestamp CreatedOn;
private String ModifiedBy;
private Timestamp ModifiedOn;
private String Description;
private String desc = "";


public Contract(){

}
public Contract(String contractId){
setContractId(contractId);
}
public Contract(String version, String status) {
setVersion(version);
setStatus(status);
}
public Contract(String financialYear, String cycle,
Contract[] contract) {
setCycle(cycle);
setFinancialYear(financialYear);

for (int i = 0; i < contract.length; i++) {
add(contract[i]);
}
}
public Contract(String financialYear, String cycle,
String version) {
setCycle(cycle);
setFinancialYear(financialYear);
setVersion(version);
}


/*Implementations*/

/**
* @return the Concantenated Description of the Period
*/
public String getDescription() {
return Description;
}
/**
* @return the contractId
*/
public String getContractId() {
return ContractId;
}
/**
* @param contractId the contractId to set
*/
public void setContractId(String contractId) {
this.ContractId=contractId;
}

/**
* @param Description the contractId to set
*/
public void setDescription(String description) {
String ds = getDescription();

if(ds==null)
ds ="";

ds = ds +description;

this.Description=ds;
}

/**
* @return the parentId
*/
public String getParentId() {
return ParentId;
}
/**
* @param parentId the parentId to set
*/
public void setParentId(String parentId) {
this.ParentId=parentId;
}
/**
* @return the version
*/
public String getVersion() {
return Version;
}
/**
* @param version the version to set
*/
public void setVersion(String version) {
setDescription(version);

this.Version=version;
}
/**
* @return the financialYear
*/
public String getFinancialYear() {
return FinancialYear;
}
/**
* @param financialYear the financialYear to set
*/
public void setFinancialYear(String financialYear) {
setDescription("-"+financialYear);
this.FinancialYear=financialYear;
}
/**
* @return the cycle
*/
public String getCycle() {
return Cycle;
}
/**
* @param cycle the cycle to set
*/
public void setCycle(String cycle) {
setDescription(cycle);
this.Cycle=cycle;
}
/**
* @return the status
*/
public String getStatus() {
return Status;
}
/**
* @param status the status to set
*/
public void setStatus(String status) {
setDescription(" ("+status+")") ;

this.Status=status;
}
/**
* @return the createdBy
*/
public String getCreatedBy() {
return CreatedBy;
}
/**
* @param createdBy the createdBy to set
*/
public void setCreatedBy(String createdBy) {
this.CreatedBy=createdBy;
}
/**
* @return the createdOn
*/
public Timestamp getCreatedOn() {
return CreatedOn;
}
/**
* @param createdOn the createdOn to set
*/
public void setCreatedOn(Timestamp createdOn) {
this.CreatedOn=createdOn;
}
/**
* @return the modifiedBy
*/
public String getModifiedBy() {
return ModifiedBy;
}
/**
* @param modifiedBy the modifiedBy to set
*/
public void setModifiedBy(String modifiedBy) {
this.ModifiedBy=modifiedBy;
}
/**
* @return the modifiedOn
*/
public Timestamp getModifiedOn() {
return ModifiedOn;
}
/**
* @param modifiedOn the modifiedOn to set
*/
public void setModifiedOn(Timestamp modifiedOn) {
this.ModifiedOn=modifiedOn;
}
/**
* @return the parent
*/
public Contract getParent() {
return Parent;
}
/**
* @param parent the parent to set
*/
public void setParent(Contract parent) {
this.Parent=parent;
}
/**
* @return the template
*/
public Contract getTemplate() {
return Template;
}
/**
* @param template the template to set
*/
public void setTemplate(Contract template) {
this.Template=template;
}
/**
* @return the templateId
*/
public String getTemplateId() {
return TemplateId;
}
/**
* @param templateId the templateId to set
*/
public void setTemplateId(String templateId) {
this.TemplateId=templateId;
}

}