bundle exception: Can't find bundle for base name

when i try to run my sample class "javaSample.java" i got this error:

java.lang.ExceptionInInitializerError
   Caused by: java.util.MissingResourceException: Can't find bundle for base name  server.ressources.credentials, locale fr_FR
at java.util.ResourceBundle.throwMissingResourceException(ResourceBundle.java:1427)
at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1250)
at java.util.ResourceBundle.getBundle(ResourceBundle.java:705)at JavaSample.<clinit>(JavaSample.java:74)

i already have the credentials file in this classpath.