diff --git a/modules/libjar/nsJAR.cpp b/modules/libjar/nsJAR.cpp
index fdde46d7578..2e028ceb342 100644
--- a/modules/libjar/nsJAR.cpp
+++ b/modules/libjar/nsJAR.cpp
@@ -400,11 +400,10 @@ nsJAR::GetCertificatePrincipal(const nsACString &aFilename, nsIPrincipal** aPrin
     return NS_OK;
 
   PRInt16 requestedStatus;
-  const char *filename = PromiseFlatCString(aFilename).get();
-  if (*filename)
+  if (!aFilename.IsEmpty())
   {
     //-- Find the item
-    nsCStringKey key(filename);
+    nsCStringKey key(aFilename);
     nsJARManifestItem* manItem = static_cast<nsJARManifestItem*>(mManifestData.Get(&key));
     if (!manItem)
       return NS_OK;
@@ -424,7 +423,7 @@ nsJAR::GetCertificatePrincipal(const nsACString &aFilename, nsIPrincipal** aPrin
     requestedStatus = mGlobalStatus;
 
   if (requestedStatus != JAR_VALID_MANIFEST)
-    ReportError(filename, requestedStatus);
+    ReportError(aFilename, requestedStatus);
   else // Valid signature
   {
     *aPrincipal = mPrincipal;
@@ -840,12 +839,12 @@ nsJAR::VerifyEntry(nsJARManifestItem* aManItem, const char* aEntryData,
   return NS_OK;
 }
 
-void nsJAR::ReportError(const char* aFilename, PRInt16 errorCode)
+void nsJAR::ReportError(const nsACString &aFilename, PRInt16 errorCode)
 {
   //-- Generate error message
   nsAutoString message; 
   message.AssignLiteral("Signature Verification Error: the signature on ");
-  if (aFilename)
+  if (!aFilename.IsEmpty())
     message.AppendWithConversion(aFilename);
   else
     message.AppendLiteral("this .jar archive");
diff --git a/modules/libjar/nsJAR.h b/modules/libjar/nsJAR.h
index b03b282c545..8725574a4e0 100644
--- a/modules/libjar/nsJAR.h
+++ b/modules/libjar/nsJAR.h
@@ -146,7 +146,7 @@ class nsJAR : public nsIZipReader
     bool                     mOpened;
 
     nsresult ParseManifest();
-    void     ReportError(const char* aFilename, PRInt16 errorCode);
+    void     ReportError(const nsACString &aFilename, PRInt16 errorCode);
     nsresult LoadEntry(const nsACString &aFilename, char** aBuf, 
                        PRUint32* aBufLen = nsnull);
     PRInt32  ReadLine(const char** src); 
@@ -156,9 +156,6 @@ class nsJAR : public nsIZipReader
 
     nsresult CalculateDigest(const char* aInBuf, PRUint32 aInBufLen,
                              nsCString& digest);
-
-    //-- Debugging
-    void DumpMetadata(const char* aMessage);
 };
 
 /**