Index: src/com/google/caja/service/HtmlHandler.java
===================================================================
--- src/com/google/caja/service/HtmlHandler.java	(revision 5334)
+++ src/com/google/caja/service/HtmlHandler.java	(working copy)
@@ -30,9 +30,7 @@
 import com.google.caja.util.ContentType;
 import com.google.caja.util.Pair;
 
-import java.io.IOException;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
+import java.io.*;
 import java.net.URI;
 import java.util.List;
 
@@ -128,8 +126,12 @@
         okToContinue &= compiler.run();
       }
     } catch (Exception e) {
+      StringWriter w = new StringWriter();
+      PrintWriter pw = new PrintWriter(w);
+      e.printStackTrace(pw);
+      pw.flush();
       mq.addMessage(ServiceMessageType.EXCEPTION_IN_SERVICE,
-          MessagePart.Factory.valueOf(e.getMessage()));
+          MessagePart.Factory.valueOf(e.getMessage() + " " + w.toString()));
       okToContinue = false;
     }