fix test

Author: wangyum

lang/java/avro/src/test/java/org/apache/avro/TestDataFileCorruption.java

@@ -87,7 +87,10 @@ void corruptedFile() throws IOException {
       assertEquals("fig", r.next().toString());
       assertFalse(r.hasNext());
     } catch (AvroRuntimeException e) {
-      assertEquals("Invalid sync!", e.getCause().getMessage());
+      assertEquals("Invalid sync marker! The sync marker in the data block doesn't match the file "
+          + "header's sync marker. This likely indicates data corruption, truncated file, "
+          + "or incorrectly concatenated Avro files. Verify file integrity and ensure proper "
+          + "file transmission or creation.", e.getCause().getMessage());
     }
 
   }