JAXB unmarshall une collection

J'ai un document XML:

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

<Log>
    <logEntry>
       <severity>WARN</severity>
       <dateTime>2011-03-17 15:25</dateTime>
       <message>Here is the text from the application</message>
       <class>(class name)</class>
       <program> TB Reception</program>
    </logEntry>

    <logEntry>
       <severity>WARN</severity>
       <dateTime>2011-03-17 15:25</dateTime>
       <message>Here is the text from the application</message>
       <class>(class name)</class>
       <program> TB Reception</program>
    </logEntry>
</Log>

et deux Pojo:

package org.jwes.jaxb.jax;

import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="Log")
public class Log {
    @XmlElementWrapper(name = "logEntry")
    private List<LogEntry> logList;

    public List<LogEntry> getLogEntries() {
        return logList;
    }

    public void setLogEntries(List<LogEntry> logList) {
        this.logList = logList;
    }


}

---

package org.jwes.jaxb.jax;
import java.io.Serializable;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
@XmlRootElement(name="LogEntry")
public class LogEntry{
private String source;
private String message;
private String severity;
private String program;
private String className;
public String getSource() {
return source;
}
public void setSource(String source) {
this.source = source;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public String getSeverity() {
return severity;
}
public void setSeverity(String severity) {
this.severity = severity;
}
public String getProgram() {
return program;
}
public void setProgram(String program) {
this.program = program;
}
@XmlElement(name = "class")
public String getClassName() {
return className;
}
public void setClassName(String className) {
this.className = className;
}
}

J'aimerais récupérer les valeurs des nœuds XML à l'aide de JAXB. J'ai écrit ce court code:

public class App 
{
public static void main( String[] args ) throws JAXBException, IOException
{
JAXBContext jc = JAXBContext.newInstance(Log.class);
Unmarshaller um = jc.createUnmarshaller();
Log logElement=(Log)um.unmarshal(new FileReader("src/main/resources/log.xml"));
System.out.println(logElement.getLogEntries().toArray().length);
}
}

Quand je le lance j'ai toujours d'obtenir une valeur de zéro.