Updated the default behaviour of the messaging error handler

java/messaging.md

@@ -681,6 +681,44 @@ private void handleError(MessagingErrorEventContext ctx) {
 }
 ```
 
+In the multitenant application, there may be race conditions in the subscription process. In this case, the message cannot be processed for the tenant because the tenant context is not available. In this case, the standard error handler acknowledges the message to prevent it from getting stuck in the message sequence. To change this behavior, the custom error handler from the example above can be extended by checking the exception type of the unknown tenant. 
+
+
+```java
+@On(service = "messaging")
+private void handleError(MessagingErrorEventContext ctx) {
+
+  String errorCode = ctx.getException().getErrorStatus().getCodeString();
+  if (errorCode.equals(CdsErrorStatuses.NO_ON_HANDLER.getCodeString()) ||
+      errorCode.equals(CdsErrorStatuses.INVALID_DATA_FORMAT.getCodeString())) {
+      // error handling for infrastructure error
+      ctx.setResult(false); // no acknowledgement
+
+    } else if (errorCode.equals(CdsErrorStatuses.TENANT_NOT_EXISTS.getCodeString())) {
+      // error handling for unknown tenant context
+
+       // tenant of the received message
+      String tenant = ctx.getTenant();
+
+      // receieved message
+      Map<String, Object> headers = ctx.getMessageHeaders(); 
+      Map<String, Object> message = ctx.getMessageData();
+
+      ctx.setResult(true); // acknowledge
+    } else {
+      // error handling for application errors
+
+      // how to access the event context of the raised exception:
+      // ctx.getException().getEventContexts().stream().findFirst().ifPresent(e -> {
+      //    String event = e.getEvent());
+      //    String payload = e.get("data"));
+      // });
+
+      ctx.setResult(true); // acknowledge
+    }
+}
+```
+
 ::: warning _❗ Warning_
 The way how unsuccessfully delivered messages are treated, fully depends on the messaging broker. Please check in section [Acknowledgement Support](#acknowledgement-support)  whether the messaging broker you are using is suitable for your error handler implementation.
 :::