diff --git a/src/java/org/apache/poi/poifs/property/DirectoryProperty.java b/src/java/org/apache/poi/poifs/property/DirectoryProperty.java
index d86e73ada..ef4ff3499 100644
--- a/src/java/org/apache/poi/poifs/property/DirectoryProperty.java
+++ b/src/java/org/apache/poi/poifs/property/DirectoryProperty.java
@@ -18,6 +18,7 @@
 package org.apache.poi.poifs.property;
 
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
@@ -119,8 +120,8 @@ public class DirectoryProperty extends Property implements Parent, Iterable<Prop
         return result;
     }
 
-    public static class PropertyComparator implements Comparator<Property> {
-
+    public static class PropertyComparator implements Comparator<Property>, Serializable {
+        
         /**
          * compare method. Assumes both parameters are non-null
          * instances of Property. One property is less than another if
diff --git a/src/ooxml/java/org/apache/poi/util/XmlSort.java b/src/ooxml/java/org/apache/poi/util/XmlSort.java
index 68d2c0874..483b657d5 100644
--- a/src/ooxml/java/org/apache/poi/util/XmlSort.java
+++ b/src/ooxml/java/org/apache/poi/util/XmlSort.java
@@ -21,6 +21,7 @@ import static org.apache.poi.POIXMLTypeLoader.DEFAULT_XML_OPTIONS;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.Comparator;
 
 import javax.xml.namespace.QName;
@@ -189,7 +190,7 @@ public final class XmlSort
      * The constructor accepts an argument indicating whether the comparison order is the same as
      * the lexicographic order of the strings or the reverse.
      */
-    public static final class QNameComparator implements Comparator<XmlCursor>
+    public static final class QNameComparator implements Comparator<XmlCursor>, Serializable
     {
         public static final int ASCENDING = 1;
         public static final int DESCENDING = 2;
diff --git a/src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFTable.java b/src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFTable.java
index 664e935d4..a1944c6ae 100644
--- a/src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFTable.java
+++ b/src/scratchpad/src/org/apache/poi/hslf/usermodel/HSLFTable.java
@@ -18,6 +18,7 @@
 package org.apache.poi.hslf.usermodel;
 
 import java.awt.geom.Rectangle2D;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -169,7 +170,7 @@ implements HSLFShapeContainer, TableShape<HSLFShape,HSLFTextParagraph> {
         updateRowHeightsProperty();
     }
 
-    private static class TableCellComparator implements Comparator<HSLFShape> {
+    private static class TableCellComparator implements Comparator<HSLFShape>, Serializable {
         public int compare( HSLFShape o1, HSLFShape o2 ) {
             Rectangle2D anchor1 = o1.getAnchor();
             Rectangle2D anchor2 = o2.getAnchor();
diff --git a/src/scratchpad/src/org/apache/poi/hsmf/datatypes/AttachmentChunks.java b/src/scratchpad/src/org/apache/poi/hsmf/datatypes/AttachmentChunks.java
index eddf6787d..1dea8e8a7 100644
--- a/src/scratchpad/src/org/apache/poi/hsmf/datatypes/AttachmentChunks.java
+++ b/src/scratchpad/src/org/apache/poi/hsmf/datatypes/AttachmentChunks.java
@@ -32,6 +32,7 @@ import static org.apache.poi.hsmf.datatypes.MAPIProperty.ATTACH_RENDERING;
 import static org.apache.poi.hsmf.datatypes.MAPIProperty.ATTACH_SIZE;
 
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
@@ -185,7 +186,7 @@ public class AttachmentChunks implements ChunkGroup {
    /**
     * Orders by the attachment number.
     */
-   public static class AttachmentChunksSorter implements Comparator<AttachmentChunks> {
+   public static class AttachmentChunksSorter implements Comparator<AttachmentChunks>, Serializable {
       public int compare(AttachmentChunks a, AttachmentChunks b) {
          return a.poifsName.compareTo(b.poifsName);
       }
diff --git a/src/scratchpad/src/org/apache/poi/hsmf/datatypes/RecipientChunks.java b/src/scratchpad/src/org/apache/poi/hsmf/datatypes/RecipientChunks.java
index 1da3e7f6c..2cfd3c480 100644
--- a/src/scratchpad/src/org/apache/poi/hsmf/datatypes/RecipientChunks.java
+++ b/src/scratchpad/src/org/apache/poi/hsmf/datatypes/RecipientChunks.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.hsmf.datatypes;
 
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -222,7 +223,7 @@ public final class RecipientChunks implements ChunkGroupWithProperties {
    /**
     * Orders by the recipient number.
     */
-   public static class RecipientChunksSorter implements Comparator<RecipientChunks> {
+   public static class RecipientChunksSorter implements Comparator<RecipientChunks>, Serializable {
       public int compare(RecipientChunks a, RecipientChunks b) {
          if(a.recipientNumber < b.recipientNumber)
             return -1;
diff --git a/src/scratchpad/src/org/apache/poi/hwpf/model/TextPieceTable.java b/src/scratchpad/src/org/apache/poi/hwpf/model/TextPieceTable.java
index baeee0c06..6a42e2b9f 100644
--- a/src/scratchpad/src/org/apache/poi/hwpf/model/TextPieceTable.java
+++ b/src/scratchpad/src/org/apache/poi/hwpf/model/TextPieceTable.java
@@ -17,6 +17,7 @@
 package org.apache.poi.hwpf.model;
 
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -497,7 +498,7 @@ public class TextPieceTable implements CharIndexTranslator
         return textPlex.toByteArray();
     }
 
-    private static class FCComparator implements Comparator<TextPiece>
+    private static class FCComparator implements Comparator<TextPiece>, Serializable
     {
         public int compare( TextPiece textPiece, TextPiece textPiece1 )
         {
diff --git a/src/scratchpad/src/org/apache/poi/hwpf/usermodel/FieldsImpl.java b/src/scratchpad/src/org/apache/poi/hwpf/usermodel/FieldsImpl.java
index 3c5eba60e..7f73e5918 100644
--- a/src/scratchpad/src/org/apache/poi/hwpf/usermodel/FieldsImpl.java
+++ b/src/scratchpad/src/org/apache/poi/hwpf/usermodel/FieldsImpl.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.hwpf.usermodel;
 
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -262,9 +263,7 @@ public class FieldsImpl implements Fields
         }
     }
 
-    private static final class PlexOfFieldComparator implements
-            Comparator<PlexOfField>
-    {
+    private static final class PlexOfFieldComparator implements Comparator<PlexOfField>, Serializable {
         public int compare( PlexOfField o1, PlexOfField o2 )
         {
             int thisVal = o1.getFcStart();