Index: SearchQuery.java
===================================================================
--- SearchQuery.java	(revision 1468833)
+++ SearchQuery.java	(working copy)
@@ -27,6 +27,7 @@
 import java.util.List;
 import java.util.Set;
 
+import javax.mail.Flags;
 import javax.mail.Flags.Flag;
 
 /**
@@ -1409,12 +1410,13 @@
     public static final class FlagCriterion extends Criterion {
         private static final long serialVersionUID = 1L;
 
-        private final Flag flag;
+        // Flags not Flag because Flags are serializable and Flag is not
+        private final Flags flag;
         private final BooleanOperator operator;
 
         private FlagCriterion(final Flag flag, final BooleanOperator operator) {
             super();
-            this.flag = flag;
+            this.flag = new Flags(flag);
             this.operator = operator;
         }
 
@@ -1424,7 +1426,9 @@
          * @return the flag, not null
          */
         public Flag getFlag() {
-            return flag;
+        	// safe because the Flags(Flag) does system flags, 
+        	// and James code also constructs FlagCriterion only with system flags
+            return flag.getSystemFlags()[0];
         }
 
         /**
@@ -1492,6 +1496,25 @@
 
     }
 
+        /**
+         * Constructs a <code>String</code> with all attributes in name = value
+         * format.
+         * 
+         * @return a <code>String</code> representation of this object.
+         */
+        public String toString() {
+            final String TAB = " ";
+
+            StringBuffer retValue = new StringBuffer();
+
+            retValue.append("FlagCriterion ( ").append("flag = ").append(this.flag).append(TAB).append("operator = ")
+                    .append(this.operator).append(TAB).append(" )");
+
+            return retValue.toString();
+        }
+
+    }
+
     /**
      * Filters on message identity.
      */