Erreur client service web java

Bonjour,

je debute sur les services web et j'utilise tomcat,axis, eclipse pour realiser un petit exemple je veux exacuter un client pour executer une fonction d'addition avec ce code java suivant :


import java.rmi.RemoteException;

import javax.xml.namespace.QName;
import javax.xml.rpc.ParameterMode;
import javax.xml.rpc.ServiceException;
import javax.xml.rpc.encoding.XMLType;

import org.apache.axis.client.Call;
import org.apache.axis.client.Service;


public class main {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Service service = new Service();
Call call;

try {
call = (Call) service.createCall();
String endpoint = "http://localhost:8080/rrr/services/calculer";

call.setTargetEndpointAddress(endpoint);
call.setOperationName(new QName("add"));

Integer i1 = new Integer(4);
Integer i2 = new Integer(6);

Integer ret = (Integer) call.invoke( new Object [] { i1, i2 });

System.out.println("resultat = " + ret);

} catch (ServiceException e) {
e.printStackTrace();
}


}

}

voici ce que je recoit comme erreur


Exception in thread "main" java.lang.ExceptionInInitializerError
at org.apache.axis.client.Service.getAxisClient(Service.java:104)
at org.apache.axis.client.Service.<init>(Service.java:113)
at main.main(main.java:20)
Caused by: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException))
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:370)
at org.apache.axis.components.logger.LogFactory.getLog(LogFactory.java:37)
at org.apache.axis.handlers.BasicHandler.<clinit>(BasicHandler.java:43)
... 3 more
Caused by: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException)
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
... 7 more
Caused by: java.lang.NullPointerException
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374)
... 8 more

merci d'avance