diff --git a/mozilla/extensions/java/xpcom/nsJavaWrapper.cpp b/mozilla/extensions/java/xpcom/nsJavaWrapper.cpp
index 3dbdbe5bec6..51be6095301 100644
--- a/mozilla/extensions/java/xpcom/nsJavaWrapper.cpp
+++ b/mozilla/extensions/java/xpcom/nsJavaWrapper.cpp
@@ -782,35 +782,22 @@ SetupParams(JNIEnv *env, const jobject aParam, PRUint8 aType, PRBool aIsOut,
     case nsXPTType::T_DOMSTRING:
     {
       LOG(("String\n"));
-      jstring data = nsnull;
-      if (!aIsOut && !aIsArrayElement) {  // 'in'
-        data = (jstring) aParam;
-      } else if (aParam) {  // 'inout' & 'array'
-        data = (jstring) env->GetObjectArrayElement((jobjectArray) aParam,
-                                                    aIndex);
+      // Expecting only 'in' and 'in dipper'
+      NS_PRECONDITION(!aIsOut, "unexpected param descriptor");
+      if (aIsOut) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      nsAString* str;
-      if (data) {
-        str = jstring_to_nsAString(env, data);
-        if (!str) {
-          rv = NS_ERROR_OUT_OF_MEMORY;
-          break;
-        }
-      } else {
-        str = nsnull;
+      jstring jstr = NS_STATIC_CAST(jstring, aParam);
+      nsAString* str = jstring_to_nsAString(env, jstr);
+      if (!str) {
+        rv = NS_ERROR_OUT_OF_MEMORY;
+        break;
       }
 
-      if (!aIsArrayElement) { // 'in' & 'inout'
-        aVariant.val.p = str;
-        aVariant.SetValIsDOMString();
-        if (aIsOut) { // 'inout'
-          aVariant.ptr = &aVariant.val;
-          aVariant.SetPtrIsData();
-        }
-      } else {  // 'array'
-        NS_STATIC_CAST(nsAString**, aVariant.val.p)[aIndex] = str;
-      }
+      aVariant.val.p = str;
+      aVariant.SetValIsDOMString();
       break;
     }
 
@@ -818,38 +805,25 @@ SetupParams(JNIEnv *env, const jobject aParam, PRUint8 aType, PRBool aIsOut,
     case nsXPTType::T_CSTRING:
     {
       LOG(("StringUTF\n"));
-      jstring data = nsnull;
-      if (!aIsOut && !aIsArrayElement) {  // 'in'
-        data = (jstring) aParam;
-      } else if (aParam) {  // 'inout' & 'array'
-        data = (jstring) env->GetObjectArrayElement((jobjectArray) aParam,
-                                                    aIndex);
+      // Expecting only 'in' and 'in dipper'
+      NS_PRECONDITION(!aIsOut, "unexpected param descriptor");
+      if (aIsOut) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      nsACString* str;
-      if (data) {
-        str = jstring_to_nsACString(env, data);
-        if (!str) {
-          rv = NS_ERROR_OUT_OF_MEMORY;
-          break;
-        }
+      jstring jstr = NS_STATIC_CAST(jstring, aParam);
+      nsACString* str = jstring_to_nsACString(env, jstr);
+      if (!str) {
+        rv = NS_ERROR_OUT_OF_MEMORY;
+        break;
+      }
+
+      aVariant.val.p = str;
+      if (aType == nsXPTType::T_CSTRING) {
+        aVariant.SetValIsCString();
       } else {
-        str = nsnull;
-      }
-
-      if (!aIsArrayElement) { // 'in' & 'inout'
-        aVariant.val.p = str;
-        if (aType == nsXPTType::T_CSTRING) {
-          aVariant.SetValIsCString();
-        } else {
-          aVariant.SetValIsUTF8String();
-        }
-        if (aIsOut) { // 'inout'
-          aVariant.ptr = &aVariant.val;
-          aVariant.SetPtrIsData();
-        }
-      } else {  // 'array'
-        NS_STATIC_CAST(nsACString**, aVariant.val.p)[aIndex] = str;
+        aVariant.SetValIsUTF8String();
       }
       break;
     }
@@ -1157,14 +1131,17 @@ FinalizeParams(JNIEnv *env, const nsXPTParamInfo &aParamInfo, PRUint8 aType,
     case nsXPTType::T_ASTRING:
     case nsXPTType::T_DOMSTRING:
     {
-      nsString* str = NS_STATIC_CAST(nsString*, aVariant.val.p);
+      NS_PRECONDITION(aParamInfo.IsIn(), "unexpected param descriptor");
+      if (!aParamInfo.IsIn()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
+      }
 
-      if ((aParamInfo.IsOut() || aParamInfo.IsDipper() || aIsArrayElement) &&
-          NS_SUCCEEDED(aInvokeResult))
-      {
+      nsString* str = NS_STATIC_CAST(nsString*, aVariant.val.p);
+      if (NS_SUCCEEDED(aInvokeResult) && aParamInfo.IsDipper()) {
         // Create Java string from returned nsString
         jstring jstr = nsnull;
-        if (str) {
+        if (str && !str->IsVoid()) {
           jstr = env->NewString((const jchar*) str->get(), str->Length());
           if (!jstr) {
             rv = NS_ERROR_OUT_OF_MEMORY;
@@ -1172,12 +1149,7 @@ FinalizeParams(JNIEnv *env, const nsXPTParamInfo &aParamInfo, PRUint8 aType,
           }
         }
 
-        if (aParamInfo.IsRetval() && !aIsArrayElement) {
-          *aParam = jstr;
-        } else if (*aParam) {
-          // put new Java string into output array
-          env->SetObjectArrayElement((jobjectArray) *aParam, aIndex, jstr);
-        }
+        *aParam = jstr;        
       }
 
       // cleanup
@@ -1190,14 +1162,17 @@ FinalizeParams(JNIEnv *env, const nsXPTParamInfo &aParamInfo, PRUint8 aType,
     case nsXPTType::T_UTF8STRING:
     case nsXPTType::T_CSTRING:
     {
-      nsCString* str = NS_STATIC_CAST(nsCString*, aVariant.val.p);
+      NS_PRECONDITION(aParamInfo.IsIn(), "unexpected param descriptor");
+      if (!aParamInfo.IsIn()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
+      }
 
-      if ((aParamInfo.IsOut() || aParamInfo.IsDipper() || aIsArrayElement) &&
-          NS_SUCCEEDED(aInvokeResult))
-      {
+      nsCString* str = NS_STATIC_CAST(nsCString*, aVariant.val.p);
+      if (NS_SUCCEEDED(aInvokeResult) && aParamInfo.IsDipper()) {
         // Create Java string from returned nsString
         jstring jstr = nsnull;
-        if (str) {
+        if (str && !str->IsVoid()) {
           jstr = env->NewStringUTF((const char*) str->get());
           if (!jstr) {
             rv = NS_ERROR_OUT_OF_MEMORY;
@@ -1205,12 +1180,7 @@ FinalizeParams(JNIEnv *env, const nsXPTParamInfo &aParamInfo, PRUint8 aType,
           }
         }
 
-        if (aParamInfo.IsRetval() && !aIsArrayElement) {
-          *aParam = jstr;
-        } else if (*aParam) {
-          // put new Java string into output array
-          env->SetObjectArrayElement((jobjectArray) *aParam, aIndex, jstr);
-        }
+        *aParam = jstr;        
       }
 
       // cleanup
@@ -1441,7 +1411,7 @@ JAVAPROXY_NATIVE(callXPCOMMethod) (JNIEnv *env, jclass that, jobject aJavaProxy,
       const nsXPTParamInfo &paramInfo = methodInfo->GetParam(i);
       params[i].type = paramInfo.GetType();
 
-      if (paramInfo.IsIn() && !paramInfo.IsDipper()) {
+      if (paramInfo.IsIn()) {
         PRUint8 type = params[i].type.TagPart();
 
         // is paramater an array?
@@ -1478,41 +1448,12 @@ JAVAPROXY_NATIVE(callXPCOMMethod) (JNIEnv *env, jclass that, jobject aJavaProxy,
         }
 
         if (NS_SUCCEEDED(rv)) {
-          rv = SetupParams(env, env->GetObjectArrayElement(aParams, i), type,
-                           paramInfo.IsOut(), iid, arrayType, arraySize,
-                           PR_FALSE, 0, params[i]);
-        }
-      } else if (paramInfo.IsDipper()) {
-        LOG(("dipper\n"));
-        switch (params[i].type.TagPart())
-        {
-          case nsXPTType::T_ASTRING:
-          case nsXPTType::T_DOMSTRING:
-          {
-            params[i].val.p = new nsString();
-            if (params[i].val.p == nsnull) {
-              rv = NS_ERROR_OUT_OF_MEMORY;
-              break;
-            }
-            params[i].SetValIsDOMString();
-            break;
+          jobject param = nsnull;
+          if (aParams && !paramInfo.IsRetval()) {
+            param = env->GetObjectArrayElement(aParams, i);
           }
-
-          case nsXPTType::T_UTF8STRING:
-          case nsXPTType::T_CSTRING:
-          {
-            params[i].val.p = new nsCString();
-            if (params[i].val.p == nsnull) {
-              rv = NS_ERROR_OUT_OF_MEMORY;
-              break;
-            }
-            params[i].SetValIsCString();
-            break;
-          }
-
-          default:
-            LOG(("unhandled dipper type\n"));
-            rv = NS_ERROR_UNEXPECTED;
+          rv = SetupParams(env, param, type, paramInfo.IsOut(), iid, arrayType,
+                           arraySize, PR_FALSE, 0, params[i]);
         }
       } else {
         LOG(("out/retval\n"));
diff --git a/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.cpp b/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.cpp
index 34512157100..28ba75a9e87 100644
--- a/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.cpp
+++ b/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.cpp
@@ -1054,7 +1054,12 @@ jstring_to_nsAString(JNIEnv* env, jstring aString)
   }
 
   nsString* str = new nsString(buf);
-  env->ReleaseStringChars(aString, buf);
+
+  if (aString) {
+    env->ReleaseStringChars(aString, buf);
+  } else {
+    str->SetIsVoid(PR_TRUE);
+  }
 
   // returns string, or nsnull if 'new' failed
   return str;
@@ -1071,7 +1076,12 @@ jstring_to_nsACString(JNIEnv* env, jstring aString)
   }
 
   nsCString* str = new nsCString(buf);
-  env->ReleaseStringUTFChars(aString, buf);
+
+  if (aString) {
+    env->ReleaseStringUTFChars(aString, buf);
+  } else {
+    str->SetIsVoid(PR_TRUE);
+  }
 
   // returns string, or nsnull if 'new' failed
   return str;
diff --git a/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.h b/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.h
index afcadc97e64..d1d845a9b70 100644
--- a/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.h
+++ b/mozilla/extensions/java/xpcom/nsJavaXPCOMBindingUtils.h
@@ -371,8 +371,9 @@ void ThrowException(JNIEnv* env, const nsresult aErrorCode,
  * @param env       Java environment pointer
  * @param aString   Java string to convert
  *
- * @return  nsAString/nsACString with same content as given Java string; or
- *          <code>nsnull</code> if out of memory
+ * @return  nsAString/nsACString with same content as given Java string;
+ *          a 'void' nsAString/nsACString object if aString is
+ *          <code>null</code>; or <code>nsnull</code> if out of memory
  */
 nsAString* jstring_to_nsAString(JNIEnv* env, jstring aString);
 nsACString* jstring_to_nsACString(JNIEnv* env, jstring aString);
diff --git a/mozilla/extensions/java/xpcom/nsJavaXPTCStub.cpp b/mozilla/extensions/java/xpcom/nsJavaXPTCStub.cpp
index ccd43edaec5..c12118f8204 100644
--- a/mozilla/extensions/java/xpcom/nsJavaXPTCStub.cpp
+++ b/mozilla/extensions/java/xpcom/nsJavaXPTCStub.cpp
@@ -412,7 +412,6 @@ nsJavaXPTCStub::CallMethod(PRUint16 aMethodIndex,
     for (PRUint8 i = 0; i < paramCount && NS_SUCCEEDED(rv); i++)
     {
       const nsXPTParamInfo &paramInfo = aMethodInfo->GetParam(i);
-      NS_ASSERTION(!paramInfo.IsDipper(), "Dipper!");
       if (!paramInfo.IsRetval()) {
         rv = SetupJavaParams(paramInfo, aMethodInfo, aMethodIndex, aParams,
                              aParams[i], java_params[i], methodSig);
@@ -558,7 +557,7 @@ nsJavaXPTCStub::CallMethod(PRUint16 aMethodIndex,
     for (PRUint8 i = 0; i < paramCount; i++)
     {
       const nsXPTParamInfo &paramInfo = aMethodInfo->GetParam(i);
-      if (paramInfo.IsIn() && !paramInfo.IsOut()) // 'in'
+      if (paramInfo.IsIn() && !paramInfo.IsOut() && !paramInfo.IsDipper()) // 'in'
         continue;
 
       // If param is null, then caller is not expecting an output value.
@@ -955,80 +954,62 @@ nsJavaXPTCStub::SetupJavaParams(const nsXPTParamInfo &aParamInfo,
     case nsXPTType::T_ASTRING:
     case nsXPTType::T_DOMSTRING:
     {
-      nsString* str = nsnull;
-      if (!aParamInfo.IsOut()) {  // 'in'
-        str = NS_STATIC_CAST(nsString*, aVariant.val.p);
-      } else if (aVariant.val.p) {  // 'inout' & 'out'
-        nsString** variant = NS_STATIC_CAST(nsString**, aVariant.val.p);
-        str = *variant;
+      // This only handle 'in' or 'in dipper' params.  In XPIDL, the 'out'
+      // descriptor is mapped to 'in dipper'.
+      NS_PRECONDITION(aParamInfo.IsIn(), "unexpected param descriptor");
+      if (!aParamInfo.IsIn()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      jstring jstr;
-      if (str) {
+      nsString* str = NS_STATIC_CAST(nsString*, aVariant.val.p);
+      if (!str) {
+        rv = NS_ERROR_FAILURE;
+        break;
+      }
+
+      jstring jstr = nsnull;
+      if (!str->IsVoid()) {
         jstr = env->NewString(str->get(), str->Length());
         if (!jstr) {
           rv = NS_ERROR_OUT_OF_MEMORY;
           break;
         }
-      } else {
-        jstr = nsnull;
       }
 
-      if (!aParamInfo.IsOut()) {  // 'in'
-        aJValue.l = jstr;
-        aMethodSig.AppendLiteral("Ljava/lang/String;");
-      } else {  // 'inout' & 'out'
-        if (aVariant.val.p) {
-          aJValue.l = env->NewObjectArray(1, stringClass, jstr);
-          if (aJValue.l == nsnull) {
-            rv = NS_ERROR_OUT_OF_MEMORY;
-            break;
-          }
-        } else {
-          aJValue.l = nsnull;
-        }
-        aMethodSig.AppendLiteral("[Ljava/lang/String;");
-      }
+      aJValue.l = jstr;
+      aMethodSig.AppendLiteral("Ljava/lang/String;");
     }
     break;
 
     case nsXPTType::T_UTF8STRING:
     case nsXPTType::T_CSTRING:
     {
-      nsCString* str = nsnull;
-      if (!aParamInfo.IsOut()) {  // 'in'
-        str = NS_STATIC_CAST(nsCString*, aVariant.val.p);
-      } else if (aVariant.val.p) {  // 'inout' & 'out'
-        nsCString** variant = NS_STATIC_CAST(nsCString**, aVariant.val.p);
-        str = *variant;
+      // This only handle 'in' or 'in dipper' params.  In XPIDL, the 'out'
+      // descriptor is mapped to 'in dipper'.
+      NS_PRECONDITION(aParamInfo.IsIn(), "unexpected param descriptor");
+      if (!aParamInfo.IsIn()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      jstring jstr;
-      if (str) {
+      nsCString* str = NS_STATIC_CAST(nsCString*, aVariant.val.p);
+      if (!str) {
+        rv = NS_ERROR_FAILURE;
+        break;
+      }
+
+      jstring jstr = nsnull;
+      if (!str->IsVoid()) {
         jstr = env->NewStringUTF(str->get());
         if (!jstr) {
           rv = NS_ERROR_OUT_OF_MEMORY;
           break;
         }
-      } else {
-        jstr = nsnull;
       }
 
-      if (!aParamInfo.IsOut()) {  // 'in'
-        aJValue.l = jstr;
-        aMethodSig.AppendLiteral("Ljava/lang/String;");
-      } else {  // 'inout' & 'out'
-        if (aVariant.val.p) {
-          aJValue.l = env->NewObjectArray(1, stringClass, jstr);
-          if (aJValue.l == nsnull) {
-            rv = NS_ERROR_OUT_OF_MEMORY;
-            break;
-          }
-        } else {
-          aJValue.l = nsnull;
-        }
-        aMethodSig.AppendLiteral("[Ljava/lang/String;");
-      }
+      aJValue.l = jstr;
+      aMethodSig.AppendLiteral("Ljava/lang/String;");
     }
     break;
 
@@ -1544,47 +1525,29 @@ nsJavaXPTCStub::FinalizeJavaParams(const nsXPTParamInfo &aParamInfo,
     case nsXPTType::T_ASTRING:
     case nsXPTType::T_DOMSTRING:
     {
-      jstring str = nsnull;
-      if (aParamInfo.IsRetval()) {  // 'retval'
-        str = (jstring) aJValue.l;
-      } else {  // 'inout' & 'out'
-        str = (jstring) env->GetObjectArrayElement((jobjectArray) aJValue.l, 0);
+      NS_PRECONDITION(aParamInfo.IsDipper(), "string argument is not dipper");
+      if (!aParamInfo.IsDipper()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      nsString** variant = NS_STATIC_CAST(nsString**, aVariant.val.p);
-      if (str) {
+      jstring jstr = (jstring) aJValue.l;
+      nsString* variant = NS_STATIC_CAST(nsString*, aVariant.val.p);
+      
+      if (jstr) {
         // Get string buffer
-        const jchar* wchar_ptr = env->GetStringChars(str, nsnull);
+        const jchar* wchar_ptr = env->GetStringChars(jstr, nsnull);
         if (!wchar_ptr) {
           rv = NS_ERROR_OUT_OF_MEMORY;
           break;
         }
 
-        if (!aParamInfo.IsRetval() && *variant) {
-          // If we were given an nsString, set it to the new string
-          nsString* string = *variant;
-          string->Assign(wchar_ptr);
-        } else {
-          // If the argument that was passed in was null, then we need to
-          // create a new string.
-          nsString* embedStr = new nsString(wchar_ptr);
-          if (embedStr) {
-            *variant = embedStr;
-          } else {
-            rv = NS_ERROR_OUT_OF_MEMORY;
-            // don't 'break'; fall through to release chars
-          }
-        }
+        variant->Assign(wchar_ptr);
 
         // release String buffer
-        env->ReleaseStringChars(str, wchar_ptr);
+        env->ReleaseStringChars(jstr, wchar_ptr);
       } else {
-        // If we were passed in a string, delete it now, and set to null.
-        // (Free only 'inout' & 'out' params)
-        if (*variant && !aParamInfo.IsRetval()) {
-          delete *variant;
-        }
-        *variant = nsnull;
+        variant->SetIsVoid(PR_TRUE);
       }
     }
     break;
@@ -1592,47 +1555,29 @@ nsJavaXPTCStub::FinalizeJavaParams(const nsXPTParamInfo &aParamInfo,
     case nsXPTType::T_UTF8STRING:
     case nsXPTType::T_CSTRING:
     {
-      jstring str = nsnull;
-      if (aParamInfo.IsRetval()) {  // 'retval'
-        str = (jstring) aJValue.l;
-      } else {  // 'inout' & 'out'
-        str = (jstring) env->GetObjectArrayElement((jobjectArray) aJValue.l, 0);
+      NS_PRECONDITION(aParamInfo.IsDipper(), "string argument is not dipper");
+      if (!aParamInfo.IsDipper()) {
+        rv = NS_ERROR_UNEXPECTED;
+        break;
       }
 
-      nsCString** variant = NS_STATIC_CAST(nsCString**, aVariant.val.p);
-      if (str) {
+      jstring jstr = (jstring) aJValue.l;
+      nsCString* variant = NS_STATIC_CAST(nsCString*, aVariant.val.p);
+      
+      if (jstr) {
         // Get string buffer
-        const char* char_ptr = env->GetStringUTFChars(str, nsnull);
+        const char* char_ptr = env->GetStringUTFChars(jstr, nsnull);
         if (!char_ptr) {
           rv = NS_ERROR_OUT_OF_MEMORY;
           break;
         }
 
-        if (!aParamInfo.IsRetval() && *variant) {
-          // If we were given an nsString, set it to the new string
-          nsCString* string = *variant;
-          string->Assign(char_ptr);
-        } else {
-          // If the argument that was passed in was null, then we need to
-          // create a new nsID.
-          nsCString* embedStr = new nsCString(char_ptr);
-          if (embedStr) {
-            *variant = embedStr;
-          } else {
-            rv = NS_ERROR_OUT_OF_MEMORY;
-            // don't 'break'; fall through to release chars
-          }
-        }
+        variant->Assign(char_ptr);
 
         // release String buffer
-        env->ReleaseStringUTFChars(str, char_ptr);
+        env->ReleaseStringUTFChars(jstr, char_ptr);
       } else {
-        // If we were passed in a string, delete it now, and set to null.
-        // (Free only 'inout' & 'out' params)
-        if (*variant && !aParamInfo.IsRetval()) {
-          delete *variant;
-        }
-        *variant = nsnull;
+        variant->SetIsVoid(PR_TRUE);
       }
     }
     break;