diff --git a/Source/com/drew/imaging/FileType.java b/Source/com/drew/imaging/FileType.java
index 9914ac50c..44a4c8a33 100644
--- a/Source/com/drew/imaging/FileType.java
+++ b/Source/com/drew/imaging/FileType.java
@@ -71,7 +71,7 @@ public enum FileType
     // Only file detection
     Aac("AAC", "Advanced Audio Coding", "audio/aac", "m4a"),
     Asf("ASF", "Advanced Systems Format", "video/x-ms-asf", "asf", "wma", "wmv"),
-    Cfbf("CFBF", "Compound File Binary Format", null, (String[])null),
+    Cfbf("CFBF", "Compound File Binary Format", null),
     Flv("FLV", "Flash Video", "video/x-flv", ".flv", ".f4v,"),
     Indd("INDD", "INDesign Document", "application/octet-stream", ".indd"),
     Mxf("MXF", "Material Exchange Format", "application/mxf", "mxf"),
@@ -88,9 +88,9 @@ public enum FileType
     @NotNull private final String _name;
     @NotNull private final String _longName;
     @Nullable private final String _mimeType;
-    private final String[] _extensions;
+    @NotNull private final String[] _extensions;
 
-    FileType(@NotNull String name, @NotNull String longName, @Nullable String mimeType, String... extensions)
+    FileType(@NotNull String name, @NotNull String longName, @Nullable String mimeType, @NotNull String... extensions)
     {
         _name = name;
         _longName = longName;
diff --git a/Tests/com/drew/imaging/FileTypeTest.java b/Tests/com/drew/imaging/FileTypeTest.java
index 5ca58e180..09201a38e 100644
--- a/Tests/com/drew/imaging/FileTypeTest.java
+++ b/Tests/com/drew/imaging/FileTypeTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 Drew Noakes and contributors
+ * Copyright 2002-2024 Drew Noakes and contributors
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
 public class FileTypeTest
@@ -41,4 +42,13 @@ public void testExtensions()
 
         assertNull(FileType.Unknown.getCommonExtension());
     }
+
+    @Test
+    public void testCommonExtension()
+    {
+        for (FileType fileType : FileType.values()) {
+            String[] extensions = fileType.getAllExtensions();
+            assertNotNull(fileType.name(), extensions);
+        }
+    }
 }