java.io.FileNotFoundException: .\cfg\users (The system cannot find the path specified)

I have created a Dynamic Web Project (to generate and send a report)

Project Hierarchy in Eclipse

Project
  src(folder)
         -metier(Package)
                  -Util.java(Class)
         -web
                  -ControlleurServlet.java (Servlet)  
  cfg(folder)
         -USERS(file) 

  WebContent
         - gui.jsp (Html form)

When I run Util class (Method : sendMail) as a Java project it's working :

Util Class :

public class Util {
    static String cvsSplitBy = ";";
public  static String MAILCONFIGURATION="./cfg/mailConfiguration";
public  static String USERS="./cfg/users";
public  static String SHIFTS="./cfg/shifts";
.
.
.

sendMail method retreive some data from files.

but when I run the project on server and invoke sendMail from the Servlet I got this error :

INFO: Server startup in 10135 ms
java.io.FileNotFoundException: .\cfg\users (The system cannot find the path specified)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(Unknown Source)
    at java.io.FileInputStream.<init>(Unknown Source)
    at metier.Util.getUsers(Util.java:130)
    at web.ControleurServlet.doGet(ControleurServlet.java:37)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1136)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Could you please help?

Regards