New improvements

src/main/java/rvc/timecalc/Main.java

@@ -37,7 +37,7 @@ public class Main {
                             null,
                             lastOvertime == null ? "0:00" : lastOvertime
                     );
-            
+
             if(!starttimeTxt.exists()) {
                 Utils.writeTextToFile(starttimeTxt, startTime);
             }

src/main/java/rvc/timecalc/Utils.java

@@ -49,6 +49,10 @@ public class Utils {
      */
     public static String readTextFromFile(final File file)
             throws IOException {
+        if(!file.exists()) {
+            //nothing to do
+            return null;
+        }
         return new String(Files.readAllBytes(file.toPath()));
     }
 }