diff --git a/vaadin-dev-server/src/main/java/com/vaadin/base/devserver/BrowserLauncher.java b/vaadin-dev-server/src/main/java/com/vaadin/base/devserver/BrowserLauncher.java
index 3009e252bec..429cdf2526e 100644
--- a/vaadin-dev-server/src/main/java/com/vaadin/base/devserver/BrowserLauncher.java
+++ b/vaadin-dev-server/src/main/java/com/vaadin/base/devserver/BrowserLauncher.java
@@ -70,18 +70,22 @@ private boolean isLaunched() {
         if (launchFile.exists()
                 && TimeUnit.MILLISECONDS.toMinutes(System.currentTimeMillis()
                         - launchFile.lastModified()) < lastModifiedDelay) {
-            try {
-                Files.writeString(launchFile.toPath(),
-                        "" + System.currentTimeMillis());
-            } catch (IOException e) {
-                LoggerFactory.getLogger(BrowserLauncher.class)
-                        .debug("Failed to write browser launched file.", e);
-            }
+            writeLaunchFile(launchFile);
             return true;
         }
         return LAUNCHED_VALUE.equals(System.getProperty(LAUNCH_TRACKER));
     }
 
+    private void writeLaunchFile(File launchFile) {
+        try {
+            Files.writeString(launchFile.toPath(),
+                    Long.toString(System.currentTimeMillis()));
+        } catch (IOException e) {
+            getLogger()
+                    .debug("Failed to write browser launched file.", e);
+        }
+    }
+
     private File getLaunchFile() {
         ApplicationConfiguration applicationConfiguration = ApplicationConfiguration
                 .get(context);
@@ -92,13 +96,7 @@ private File getLaunchFile() {
 
     private void setLaunched() {
         // write launch file and update modified timestamp.
-        try {
-            Files.writeString(getLaunchFile().toPath(),
-                    "" + System.currentTimeMillis());
-        } catch (IOException e) {
-            LoggerFactory.getLogger(BrowserLauncher.class)
-                    .debug("Failed to write browser launched file.", e);
-        }
+        writeLaunchFile(getLaunchFile());
         System.setProperty(LAUNCH_TRACKER, LAUNCHED_VALUE);
     }