Index: src/org/openstreetmap/josm/actions/ShowStatusReportAction.java
===================================================================
--- src/org/openstreetmap/josm/actions/ShowStatusReportAction.java	(revision 17811)
+++ src/org/openstreetmap/josm/actions/ShowStatusReportAction.java	(working copy)
@@ -95,7 +95,8 @@
         if (!buildNumber.isEmpty()) {
             text.format("OS Build number: %s%n", buildNumber);
         }
-        text.format("Memory Usage: %d MB / %d MB (%d MB allocated, but free)%n",
+
+        text.format(Locale.ENGLISH, "Memory Usage: %d MB / %d MB (%d MB allocated, but free)%n",
                 Runtime.getRuntime().totalMemory() / 1024 / 1024,
                 Runtime.getRuntime().maxMemory() / 1024 / 1024,
                 Runtime.getRuntime().freeMemory() / 1024 / 1024);
@@ -113,7 +114,7 @@
                 if (dm != null) {
                     AffineTransform transform = gd.getDefaultConfiguration().getDefaultTransform();
                     // Java 11: use DisplayMode#toString
-                    text.format(" %d\u00D7%d (scaling %.2f\u00D7%.2f)",
+                    text.format(Locale.ENGLISH, " %d\u00D7%d (scaling %.2f\u00D7%.2f)",
                             dm.getWidth(), dm.getHeight(), transform.getScaleX(), transform.getScaleY());
                 }
             }
@@ -140,6 +141,7 @@
                 text.format("System property %s: %s%n", name, value);
             }
         }
+        text.format("Numbers with local locale: %s -> %d%n", Integer.toString(1_234_567_890) , 1_234_567_890);
 
         if (PlatformManager.isPlatformUnixoid()) {
             PlatformHookUnixoid platform = (PlatformHookUnixoid) PlatformManager.getPlatform();
Index: src/org/openstreetmap/josm/tools/Logging.java
===================================================================
--- src/org/openstreetmap/josm/tools/Logging.java	(revision 17811)
+++ src/org/openstreetmap/josm/tools/Logging.java	(working copy)
@@ -11,6 +11,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.function.Supplier;
 import java.util.logging.ConsoleHandler;
 import java.util.logging.Handler;
@@ -495,7 +496,7 @@
                 return;
             }
 
-            String msg = String.format("%09.3f %s%s", startup.elapsed() / 1000., getPrefix(record), record.getMessage());
+            String msg = String.format(Locale.ENGLISH,"%09.3f %s%s", startup.elapsed() / 1000., getPrefix(record), record.getMessage());
 
             // Only remember first line of message
             int idx = msg.indexOf('\n');