fine tune configuration errors

src/ulo-storage-applications/src/main/java/info/mathhub/uloapi/config/Config.java

@@ -3,6 +3,7 @@ package info.mathhub.uloapi.config;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.MissingResourceException;
 import java.util.ResourceBundle;
 
 public class Config {
@@ -40,7 +41,7 @@ public class Config {
             return environmentValue;
         }
 
-        log.debug("could not read environment variable {}, falling back to configuration file", environmentKey);
+        log.info("could not read environment variable {}, falling back to configuration file", environmentKey);
 
         // try to read the configuration from the configuration file;
         // this is useful when debugging and running this application as
@@ -49,12 +50,12 @@ public class Config {
         try {
             final ResourceBundle bundle = ResourceBundle.getBundle("uloapi");
             return bundle.getString(configFileKey);
-        } catch (NullPointerException e) {
+        } catch (NullPointerException | MissingResourceException | ClassCastException e) {
             log.warn(e.getMessage());
             log.error("could not look up configuration option {}/{}; aborting", environmentKey, configFileKey);
             System.exit(1);
         }
 
-        throw new IllegalStateException("should not be reachable");
+        throw new IllegalStateException("could not load configuration");
     }
 }