more Java changes & tests

4 files changed, 468 insertions, 376 deletions

diff --git a/cpp/src/Slice/JavaUtil.cpp b/cpp/src/Slice/JavaUtil.cpp
index a1dabf6d6dc..781b020c0c8 100644
--- a/cpp/src/Slice/JavaUtil.cpp
+++ b/cpp/src/Slice/JavaUtil.cpp
@@ -551,33 +551,20 @@ Slice::JavaGenerator::getStaticId(const TypePtr& type, const string& package) co
 }
 
 bool
-Slice::JavaGenerator::useOptionalMapping(const ParamDeclPtr& p)
+Slice::JavaGenerator::useOptionalMapping(const OperationPtr& p)
 {
-    if(p->optional())
-    {
-        //
-        // Optional in parameters can be marked with the "java:optional" metadata to force
-        // the mapping to use the Ice.Optional types. The tag can also be applied to an
-        // operation or its interface.
-        //
-        // Without the tag, in parameters use the normal (non-optional) mapping.
-        //
-        if(!p->isOutParam())
-        {
-            static const string tag = "java:optional";
-
-            OperationPtr op = OperationPtr::dynamicCast(p->container());
-            assert(op);
-            ClassDefPtr cl = ClassDefPtr::dynamicCast(op->container());
-            assert(cl);
-
-            return p->hasMetaData(tag) || op->hasMetaData(tag) || cl->hasMetaData(tag);
-        }
+    //
+    // The "java:optional" metadata can be applied to an operation or its
+    // interface to force the mapping to use the Ice.Optional types.
+    //
+    // Without the tag, parameters use the normal (non-optional) mapping.
+    //
+    static const string tag = "java:optional";
 
-        return true;
-    }
+    ClassDefPtr cl = ClassDefPtr::dynamicCast(p->container());
+    assert(cl);
 
-    return false;
+    return p->hasMetaData(tag) || cl->hasMetaData(tag);
 }
 
 string
@@ -923,7 +910,8 @@ void
 Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                                                 const string& package,
                                                 const TypePtr& type,
-                                                OptionalMode optional,
+                                                OptionalMode mode,
+                                                bool optionalMapping,
                                                 int tag,
                                                 const string& param,
                                                 bool marshal,
@@ -934,7 +922,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 {
     string stream = marshal ? "__os" : "__is";
     string v;
-    if(holder && optional == OptionalNone)
+    if(holder)
     {
         v = param + ".value";
     }
@@ -943,6 +931,8 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         v = param;
     }
 
+    const bool optionalParam = mode == OptionalInParam || mode == OptionalOutParam || mode == OptionalReturnParam;
+
     BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
     if(builtin)
     {
@@ -952,7 +942,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeByte(" << tag << ", " << v << ");";
                     }
@@ -963,7 +953,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readByte(" << tag << ", " << v << ");";
                     }
@@ -978,7 +968,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeBool(" << tag << ", " << v << ");";
                     }
@@ -989,7 +979,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readBool(" << tag << ", " << v << ");";
                     }
@@ -1004,7 +994,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeShort(" << tag << ", " << v << ");";
                     }
@@ -1015,7 +1005,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readShort(" << tag << ", " << v << ");";
                     }
@@ -1030,7 +1020,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeInt(" << tag << ", " << v << ");";
                     }
@@ -1041,7 +1031,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readInt(" << tag << ", " << v << ");";
                     }
@@ -1056,7 +1046,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeLong(" << tag << ", " << v << ");";
                     }
@@ -1067,7 +1057,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readLong(" << tag << ", " << v << ");";
                     }
@@ -1082,7 +1072,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeFloat(" << tag << ", " << v << ");";
                     }
@@ -1093,7 +1083,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readFloat(" << tag << ", " << v << ");";
                     }
@@ -1108,7 +1098,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeDouble(" << tag << ", " << v << ");";
                     }
@@ -1119,7 +1109,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readDouble(" << tag << ", " << v << ");";
                     }
@@ -1134,7 +1124,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeString(" << tag << ", " << v << ");";
                     }
@@ -1145,7 +1135,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readString(" << tag << ", " << v << ");";
                     }
@@ -1160,7 +1150,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeObject(" << tag << ", " << v << ");";
                     }
@@ -1171,11 +1161,11 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readObject(" << tag << ", " << param << ");";
                     }
-                    else if(holder && optional == OptionalNone)
+                    else if(holder && mode == OptionalNone)
                     {
                         out << nl << stream << ".readObject(" << param << ");";
                     }
@@ -1197,11 +1187,11 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".writeProxy(" << tag << ", " << v << ");";
                     }
-                    else if(optional == OptionalMember)
+                    else if(mode == OptionalMember)
                     {
                         out << nl << stream << ".startSize();";
                         out << nl << stream << ".writeProxy(" << v << ");";
@@ -1214,11 +1204,11 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(isOptionalParam(optional))
+                    if(optionalParam)
                     {
                         out << nl << stream << ".readProxy(" << tag << ", " << v << ");";
                     }
-                    else if(optional == OptionalMember)
+                    else if(mode == OptionalMember)
                     {
                         out << nl << stream << ".skip(4);";
                         out << nl << v << " = " << stream << ".readProxy();";
@@ -1245,29 +1235,29 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         string typeS = typeToString(type, TypeModeIn, package);
         if(marshal)
         {
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
-                if(optional == OptionalInParamReq)
+                if(optionalMapping)
                 {
-                    out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
+                    out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt(" << tag
+                        << ", " << getOptionalType(type) << "))";
                     out << sb;
                     out << nl << stream << ".startSize();";
-                    out << nl << typeS << "Helper.__write(" << stream << ", " << v << ");";
+                    out << nl << typeS << "Helper.__write(" << stream << ", " << v << ".get());";
                     out << nl << stream << ".endSize();";
                     out << eb;
                 }
                 else
                 {
-                    out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt(" << tag
-                        << ", " << getOptionalType(type) << "))";
+                    out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
                     out << sb;
                     out << nl << stream << ".startSize();";
-                    out << nl << typeS << "Helper.__write(" << stream << ", " << v << ".get());";
+                    out << nl << typeS << "Helper.__write(" << stream << ", " << v << ");";
                     out << nl << stream << ".endSize();";
                     out << eb;
                 }
             }
-            else if(optional == OptionalMember)
+            else if(mode == OptionalMember)
             {
                 out << nl << stream << ".startSize();";
                 out << nl << typeS << "Helper.__write(" << stream << ", " << v << ");";
@@ -1280,14 +1270,14 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         }
         else
         {
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
                 out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
                 out << sb;
                 out << nl << stream << ".skip(4);";
                 out << nl << v << ".set(" << typeS << "Helper.__read(" << stream << "));";
                 out << eb;
-                if(optional == OptionalOutParam)
+                if(mode == OptionalOutParam)
                 {
                     out << nl << "else";
                     out << sb;
@@ -1295,7 +1285,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     out << eb;
                 }
             }
-            else if(optional == OptionalMember)
+            else if(mode == OptionalMember)
             {
                 out << nl << stream << ".skip(4);";
                 out << nl << v << " = " << typeS << "Helper.__read(" << stream << ");";
@@ -1313,7 +1303,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
     {
         if(marshal)
         {
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
                 out << nl << stream << ".writeObject(" << tag << ", " << v << ");";
             }
@@ -1324,7 +1314,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         }
         else
         {
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
                 string typeS = typeToString(type, TypeModeIn, package);
                 out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
@@ -1332,7 +1322,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 out << nl << stream << ".readObject(new Ice.OptionalObject(" << v << ", " << typeS << ".class, "
                     << getStaticId(type, package) << "));";
                 out << eb;
-                if(optional == OptionalOutParam)
+                if(mode == OptionalOutParam)
                 {
                     out << nl << "else";
                     out << sb;
@@ -1342,7 +1332,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             }
             else
             {
-                if(holder && optional == OptionalNone)
+                if(holder && mode == OptionalNone)
                 {
                     out << nl << stream << ".readObject(" << param << ");";
                 }
@@ -1367,23 +1357,23 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
     {
         if(marshal)
         {
-            if(optional != OptionalNone)
+            if(optionalParam || mode == OptionalMember)
             {
                 string val;
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
-                    if(optional == OptionalInParamReq)
-                    {
-                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
-                        val = v;
-                    }
-                    else
+                    if(optionalMapping)
                     {
                         out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt("
                             << tag << ", " << getOptionalType(type) << "))";
                         val = v + ".get()";
                     }
+                    else
+                    {
+                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
+                        val = v;
+                    }
 
                     out << sb;
                 }
@@ -1404,7 +1394,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     out << nl << val << ".__write(" << stream << ");";
                 }
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     out << eb;
                 }
@@ -1418,7 +1408,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
 
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
                 out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
                 out << sb;
@@ -1438,7 +1428,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
                 out << eb;
 
-                if(optional == OptionalOutParam)
+                if(mode == OptionalOutParam)
                 {
                     out << nl << "else";
                     out << sb;
@@ -1446,7 +1436,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     out << eb;
                 }
             }
-            else if(optional == OptionalMember)
+            else if(mode == OptionalMember)
             {
                 if(st->isVariableLength())
                 {
@@ -1473,21 +1463,21 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
     {
         if(marshal)
         {
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
-                if(optional == OptionalInParamReq)
+                if(optionalMapping)
                 {
-                    out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
+                    out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt(" << tag
+                        << ", " << getOptionalType(type) << "))";
                     out << sb;
-                    out << nl << v << ".__write(" << stream << ");";
+                    out << nl << v << ".get().__write(" << stream << ");";
                     out << eb;
                 }
                 else
                 {
-                    out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt(" << tag
-                        << ", " << getOptionalType(type) << "))";
+                    out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
                     out << sb;
-                    out << nl << v << ".get().__write(" << stream << ");";
+                    out << nl << v << ".__write(" << stream << ");";
                     out << eb;
                 }
             }
@@ -1500,13 +1490,13 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
 
-            if(isOptionalParam(optional))
+            if(optionalParam)
             {
                 out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
                 out << sb;
                 out << nl << v << ".set(" << typeS << ".__read(" << stream << "));";
                 out << eb;
-                if(optional == OptionalOutParam)
+                if(mode == OptionalOutParam)
                 {
                     out << nl << "else";
                     out << sb;
@@ -1525,7 +1515,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
     DictionaryPtr dict = DictionaryPtr::dynamicCast(type);
     if(dict)
     {
-        if(optional != OptionalNone)
+        if(optionalParam || mode == OptionalMember)
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
             TypePtr keyType = dict->keyType();
@@ -1533,24 +1523,24 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
             if(marshal)
             {
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
-                    if(optional == OptionalInParamReq)
+                    if(optionalMapping)
                     {
-                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
+                        out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt("
+                            << tag << ", " << getOptionalType(type) << "))";
                         out << sb;
                     }
                     else
                     {
-                        out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt("
-                            << tag << ", " << getOptionalType(type) << "))";
+                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
                         out << sb;
                     }
                 }
 
                 if(keyType->isVariableLength() || valueType->isVariableLength())
                 {
-                    string d = isOptionalParam(optional) && optional != OptionalInParamReq ? v + ".get()" : v;
+                    string d = optionalParam && optionalMapping ? v + ".get()" : v;
                     out << nl << stream << ".startSize();";
                     writeDictionaryMarshalUnmarshalCode(out, package, dict, d, marshal, iter, true, metaData);
                     out << nl << stream << ".endSize();";
@@ -1559,7 +1549,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                 {
                     const int wireSize = keyType->minWireSize() + valueType->minWireSize();
                     string tmpName;
-                    if(isOptionalParam(optional) && optional != OptionalInParamReq)
+                    if(optionalParam && optionalMapping)
                     {
                         tmpName = "__optDict";
                         out << nl << "final " << typeS << ' ' << tmpName << " = " << v << ".get();";
@@ -1568,14 +1558,13 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     {
                         tmpName = v;
                     }
-                    out << nl << "final int __optSize = " << tmpName << " == null ? 0 : " << tmpName
-                        << ".size();";
+                    out << nl << "final int __optSize = " << tmpName << " == null ? 0 : " << tmpName << ".size();";
                     out << nl << stream << ".writeSize(__optSize > 254 ? __optSize * " << wireSize
                         << " + 5 : __optSize * " << wireSize << " + 1);";
                     writeDictionaryMarshalUnmarshalCode(out, package, dict, tmpName, marshal, iter, true, metaData);
                 }
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     out << eb;
                 }
@@ -1584,7 +1573,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             {
                 string tmpName;
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     tmpName = "__optDict";
                     out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
@@ -1607,11 +1596,11 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
                 writeDictionaryMarshalUnmarshalCode(out, package, dict, tmpName, marshal, iter, true, metaData);
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     out << nl << v << ".set(" << tmpName << ");";
                     out << eb;
-                    if(optional == OptionalOutParam)
+                    if(mode == OptionalOutParam)
                     {
                         out << nl << "else";
                         out << sb;
@@ -1631,13 +1620,13 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
     SequencePtr seq = SequencePtr::dynamicCast(type);
     if(seq)
     {
-        if(optional != OptionalNone)
+        if(optionalParam || mode == OptionalMember)
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
             TypePtr elemType = seq->type();
             BuiltinPtr elemBuiltin = BuiltinPtr::dynamicCast(elemType);
 
-            if(isOptionalParam(optional) && elemBuiltin && elemBuiltin->kind() != Builtin::KindObject &&
+            if(optionalParam && elemBuiltin && elemBuiltin->kind() != Builtin::KindObject &&
                elemBuiltin->kind() != Builtin::KindObjectProxy && !hasTypeMetaData(seq, metaData))
             {
                 static const char* builtinTable[] =
@@ -1692,16 +1681,16 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
             if(marshal)
             {
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
-                    if(optional == OptionalInParamReq)
+                    if(optionalMapping)
                     {
-                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
+                        out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt("
+                            << tag << ", " << getOptionalType(type) << "))";
                     }
                     else
                     {
-                        out << nl << "if(" << v << " != null && " << v << ".isSet() && " << stream << ".writeOpt("
-                            << tag << ", " << getOptionalType(type) << "))";
+                        out << nl << "if(" << stream << ".writeOpt(" << tag << ", " << getOptionalType(type) << "))";
                     }
 
                     out << sb;
@@ -1709,7 +1698,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
                 if(elemType->isVariableLength())
                 {
-                    string s = isOptionalParam(optional) && optional != OptionalInParamReq ? v + ".get()" : v;
+                    string s = optionalParam && optionalMapping ? v + ".get()" : v;
                     out << nl << stream << ".startSize();";
                     writeSequenceMarshalUnmarshalCode(out, package, seq, s, marshal, iter, true, metaData);
                     out << nl << stream << ".endSize();";
@@ -1723,7 +1712,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     //
 
                     string tmpName;
-                    if(isOptionalParam(optional) && optional != OptionalInParamReq)
+                    if(optionalParam && optionalMapping)
                     {
                         tmpName = "__optSeq";
                         out << nl << "final " << typeS << ' ' << tmpName << " = " << v << ".get();";
@@ -1760,7 +1749,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     //
                     // This just writes a byte sequence.
                     //
-                    string s = isOptionalParam(optional) && optional != OptionalInParamReq ? v + ".get()" : v;
+                    string s = optionalParam && optionalMapping ? v + ".get()" : v;
                     writeSequenceMarshalUnmarshalCode(out, package, seq, s, marshal, iter, true, metaData);
                 }
                 else
@@ -1770,7 +1759,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     //
 
                     string tmpName;
-                    if(isOptionalParam(optional) && optional != OptionalInParamReq)
+                    if(optionalParam && optionalMapping)
                     {
                         tmpName = "__optSeq";
                         out << nl << "final " << typeS << ' ' << tmpName << " = " << v << ".get();";
@@ -1803,7 +1792,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
                     writeSequenceMarshalUnmarshalCode(out, package, seq, tmpName, marshal, iter, true, metaData);
                 }
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     out << eb;
                 }
@@ -1811,7 +1800,7 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
             else
             {
                 string tmpName;
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     tmpName = "__optSeq";
                     out << nl << "if(" << stream << ".readOpt(" << tag << ", " << getOptionalType(type) << "))";
@@ -1853,11 +1842,11 @@ Slice::JavaGenerator::writeMarshalUnmarshalCode(Output& out,
 
                 writeSequenceMarshalUnmarshalCode(out, package, seq, tmpName, marshal, iter, true, metaData);
 
-                if(isOptionalParam(optional))
+                if(optionalParam)
                 {
                     out << nl << v << ".set(" << tmpName << ");";
                     out << eb;
-                    if(optional == OptionalOutParam)
+                    if(mode == OptionalOutParam)
                     {
                         out << nl << "else";
                         out << sb;
@@ -1982,7 +1971,7 @@ Slice::JavaGenerator::writeDictionaryMarshalUnmarshalCode(Output& out,
                 arg = "__e.getValue()";
                 type = value;
             }
-            writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, true, iter, false);
+            writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, arg, true, iter, false);
         }
         out << eb;
         out << eb;
@@ -2016,14 +2005,15 @@ Slice::JavaGenerator::writeDictionaryMarshalUnmarshalCode(Output& out,
             {
                 string keyTypeStr = typeToObjectString(key, TypeModeIn, package);
                 string valueTypeStr = typeToObjectString(value, TypeModeIn, package);
-                writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, false, iter, false, StringList(),
+                writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, arg, false, iter, false,
+                                          StringList(),
                                           "new IceInternal.DictionaryPatcher<" + keyTypeStr + ", " + valueTypeStr +
                                           ">(" + v + ", " + typeS + ".class, \"" + type->typeId() + "\", __key)");
             }
             else
             {
                 out << nl << typeS << ' ' << arg << ';';
-                writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, false, iter, false);
+                writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, arg, false, iter, false);
             }
         }
         BuiltinPtr builtin = BuiltinPtr::dynamicCast(value);
@@ -2190,7 +2180,7 @@ Slice::JavaGenerator::writeSequenceMarshalUnmarshalCode(Output& out,
             string typeS = typeToString(type, TypeModeIn, package);
             out << nl << "for(" << typeS << " __elem : " << v << ')';
             out << sb;
-            writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", true, iter, false);
+            writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, "__elem", true, iter, false);
             out << eb;
             out << eb; // else
         }
@@ -2237,13 +2227,13 @@ Slice::JavaGenerator::writeSequenceMarshalUnmarshalCode(Output& out,
                 ostringstream patchParams;
                 patchParams << "new IceInternal.ListPatcher<" << origContentS << ">(" << v << ", " << origContentS
                             << ".class, __type" << iter << ", __i" << iter << ')';
-                writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", false, iter, false,
-                                          StringList(), patchParams.str());
+                writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, "__elem", false, iter,
+                                          false, StringList(), patchParams.str());
             }
             else
             {
                 out << nl << cont << " __elem;";
-                writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", false, iter, false);
+                writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, "__elem", false, iter, false);
             }
             if(!isObject)
             {
@@ -2382,7 +2372,7 @@ Slice::JavaGenerator::writeSequenceMarshalUnmarshalCode(Output& out,
                 ostringstream o;
                 o << v << "[__i" << iter << "]";
                 iter++;
-                writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), true, iter, false);
+                writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, o.str(), true, iter, false);
                 out << eb;
                 out << eb;
             }
@@ -2467,12 +2457,12 @@ Slice::JavaGenerator::writeSequenceMarshalUnmarshalCode(Output& out,
                 {
                     patchParams << "new IceInternal.SequencePatcher(" << v << ", " << origContentS
                                 << ".class, __type" << iter << ", __i" << iter << ')';
-                    writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), false, iter, false,
-                                              StringList(), patchParams.str());
+                    writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, o.str(), false, iter,
+                                              false, StringList(), patchParams.str());
                 }
                 else
                 {
-                    writeMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), false, iter, false);
+                    writeMarshalUnmarshalCode(out, package, type, OptionalNone, false, 0, o.str(), false, iter, false);
                 }
                 out << eb;
                 iter++;
@@ -2485,7 +2475,7 @@ void
 Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
                                                       const string& package,
                                                       const TypePtr& type,
-                                                      OptionalMode optional,
+                                                      bool optional,
                                                       int tag,
                                                       const string& param,
                                                       bool marshal,
@@ -2494,11 +2484,9 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
                                                       const StringList& metaData,
                                                       const string& patchParams)
 {
-    assert(optional == OptionalNone || optional == OptionalMember); // Stream API doesn't support Ice.Optional<>.
-
     string stream = marshal ? "__outS" : "__inS";
     string v;
-    if(holder && optional == OptionalNone)
+    if(holder && !optional)
     {
         v = param + ".value";
     }
@@ -2616,7 +2604,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(holder && optional == OptionalNone)
+                    if(holder && !optional)
                     {
                         out << nl << stream << ".readObject(" << param << ");";
                     }
@@ -2638,7 +2626,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
             {
                 if(marshal)
                 {
-                    if(optional == OptionalMember)
+                    if(optional)
                     {
                         out << nl << stream << ".startSize();";
                         out << nl << stream << ".writeProxy(" << v << ");";
@@ -2651,7 +2639,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
                 }
                 else
                 {
-                    if(optional == OptionalMember)
+                    if(optional)
                     {
                         out << nl << stream << ".skip(4);";
                     }
@@ -2674,7 +2662,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
         string typeS = typeToString(type, TypeModeIn, package);
         if(marshal)
         {
-            if(optional == OptionalMember)
+            if(optional)
             {
                 out << nl << stream << ".startSize();";
                 out << nl << typeS << "Helper.write(" << stream << ", " << v << ");";
@@ -2687,7 +2675,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
         }
         else
         {
-            if(optional == OptionalMember)
+            if(optional)
             {
                 out << nl << stream << ".skip(4);";
             }
@@ -2705,7 +2693,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
         }
         else
         {
-            if(holder && optional == OptionalNone)
+            if(holder && !optional)
             {
                 out << nl << stream << ".readObject(" << param << ");";
             }
@@ -2729,7 +2717,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
     {
         if(marshal)
         {
-            if(optional != OptionalNone)
+            if(optional)
             {
                 if(st->isVariableLength())
                 {
@@ -2751,7 +2739,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
         else
         {
             string typeS = typeToString(type, TypeModeIn, package);
-            if(optional == OptionalMember)
+            if(optional)
             {
                 if(st->isVariableLength())
                 {
@@ -2791,7 +2779,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
     DictionaryPtr dict = DictionaryPtr::dynamicCast(type);
     if(dict)
     {
-        if(optional != OptionalNone)
+        if(optional)
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
             TypePtr keyType = dict->keyType();
@@ -2838,7 +2826,7 @@ Slice::JavaGenerator::writeStreamMarshalUnmarshalCode(Output& out,
     SequencePtr seq = SequencePtr::dynamicCast(type);
     if(seq)
     {
-        if(optional != OptionalNone)
+        if(optional)
         {
             string typeS = typeToString(type, TypeModeIn, package, metaData);
             TypePtr elemType = seq->type();
@@ -3066,7 +3054,7 @@ Slice::JavaGenerator::writeStreamDictionaryMarshalUnmarshalCode(Output& out,
                 arg = "__e.getValue()";
                 type = value;
             }
-            writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, true, iter, false);
+            writeStreamMarshalUnmarshalCode(out, package, type, false, 0, arg, true, iter, false);
         }
         out << eb;
         out << eb;
@@ -3101,7 +3089,7 @@ Slice::JavaGenerator::writeStreamDictionaryMarshalUnmarshalCode(Output& out,
             {
                 string keyTypeStr = typeToObjectString(key, TypeModeIn, package);
                 string valueTypeStr = typeToObjectString(value, TypeModeIn, package);
-                writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, false, iter, false,
+                writeStreamMarshalUnmarshalCode(out, package, type, false, 0, arg, false, iter, false,
                                                 StringList(), "new IceInternal.DictionaryPatcher<" + keyTypeStr +
                                                 ", " + valueTypeStr + ">(" + v + ", " + s + ".class, \"" +
                                                 type->typeId() + "\", __key)");
@@ -3109,7 +3097,7 @@ Slice::JavaGenerator::writeStreamDictionaryMarshalUnmarshalCode(Output& out,
             else
             {
                 out << nl << s << ' ' << arg << ';';
-                writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, arg, false, iter, false);
+                writeStreamMarshalUnmarshalCode(out, package, type, false, 0, arg, false, iter, false);
             }
         }
         BuiltinPtr builtin = BuiltinPtr::dynamicCast(value);
@@ -3275,7 +3263,7 @@ Slice::JavaGenerator::writeStreamSequenceMarshalUnmarshalCode(Output& out,
             string typeS = typeToString(type, TypeModeIn, package);
             out << nl << "for(" << typeS << " __elem : " << v << ')';
             out << sb;
-            writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", true, iter, false);
+            writeStreamMarshalUnmarshalCode(out, package, type, false, 0, "__elem", true, iter, false);
             out << eb;
             out << eb; // else
         }
@@ -3322,13 +3310,13 @@ Slice::JavaGenerator::writeStreamSequenceMarshalUnmarshalCode(Output& out,
                 ostringstream patchParams;
                 patchParams << "new IceInternal.ListPatcher<" << origContentS << ">(" << v << ", " << origContentS
                             << ".class, __type" << iter << ", __i" << iter << ')';
-                writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", false, iter, false,
+                writeStreamMarshalUnmarshalCode(out, package, type, false, 0, "__elem", false, iter, false,
                                                 StringList(), patchParams.str());
             }
             else
             {
                 out << nl << cont << " __elem;";
-                writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, "__elem", false, iter, false);
+                writeStreamMarshalUnmarshalCode(out, package, type, false, 0, "__elem", false, iter, false);
             }
             if(!isObject)
             {
@@ -3467,7 +3455,7 @@ Slice::JavaGenerator::writeStreamSequenceMarshalUnmarshalCode(Output& out,
                 ostringstream o;
                 o << v << "[__i" << iter << "]";
                 iter++;
-                writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), true, iter, false);
+                writeStreamMarshalUnmarshalCode(out, package, type, false, 0, o.str(), true, iter, false);
                 out << eb;
                 out << eb;
             }
@@ -3552,12 +3540,12 @@ Slice::JavaGenerator::writeStreamSequenceMarshalUnmarshalCode(Output& out,
                 {
                     patchParams << "new IceInternal.SequencePatcher(" << v << ", " << origContentS
                                 << ".class, __type" << iter << ", __i" << iter << ')';
-                    writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), false, iter, false,
+                    writeStreamMarshalUnmarshalCode(out, package, type, false, 0, o.str(), false, iter, false,
                                                     StringList(), patchParams.str());
                 }
                 else
                 {
-                    writeStreamMarshalUnmarshalCode(out, package, type, OptionalNone, 0, o.str(), false, iter, false);
+                    writeStreamMarshalUnmarshalCode(out, package, type, false, 0, o.str(), false, iter, false);
                 }
                 out << eb;
                 iter++;
diff --git a/cpp/src/slice2freezej/Main.cpp b/cpp/src/slice2freezej/Main.cpp
index 4a90ca266d0..9f85a9f5536 100755
--- a/cpp/src/slice2freezej/Main.cpp
+++ b/cpp/src/slice2freezej/Main.cpp
@@ -903,7 +903,7 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
             out << nl << "__os.startWriteEncaps();";
         }
         iter = 0;
-        writeMarshalUnmarshalCode(out, "", type, OptionalNone, 0, valS, true, iter, false);
+        writeMarshalUnmarshalCode(out, "", type, OptionalNone, false, 0, valS, true, iter, false);
         if(type->usesClasses())
         {
             out << nl << "__os.writePendingObjects();";
@@ -996,7 +996,7 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
             case Builtin::KindObjectProxy:
             case Builtin::KindLocalObject:
             {
-                writeMarshalUnmarshalCode(out, "", type, OptionalNone, 0, "__r", false, iter, false, metaData,
+                writeMarshalUnmarshalCode(out, "", type, OptionalNone, false, 0, "__r", false, iter, false, metaData,
                                           patchParams);
                 break;
             }
@@ -1004,7 +1004,8 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
         }
         else
         {
-            writeMarshalUnmarshalCode(out, "", type, OptionalNone, 0, "__r", false, iter, false, metaData, patchParams);
+            writeMarshalUnmarshalCode(out, "", type, OptionalNone, false, 0, "__r", false, iter, false, metaData,
+                                      patchParams);
         }
         if(type->usesClasses())
         {
@@ -1069,7 +1070,7 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
             out << nl << "IceInternal.BasicStream __os = "
                 << "new IceInternal.BasicStream(IceInternal.Util.getInstance(communicator), encoding, true, false);";
             int iter = 0;
-            writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, 0, keyS, true, iter, false);
+            writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, false, 0, keyS, true, iter, false);
             assert(!indexTypes[i]->usesClasses());
 
             out << nl << "IceInternal.Buffer buf = __os.prepareWrite();";
@@ -1153,7 +1154,7 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
                 case Builtin::KindObjectProxy:
                 case Builtin::KindLocalObject:
                 {
-                    writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, 0, "r", false, iter, false,
+                    writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, false, 0, "r", false, iter, false,
                                               metaData, patchParams);
                     break;
                 }
@@ -1161,8 +1162,8 @@ FreezeGenerator::generate(UnitPtr& u, const Dict& dict)
             }
             else
             {
-                writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, 0, "r", false, iter, false, metaData,
-                                          patchParams);
+                writeMarshalUnmarshalCode(out, "", indexTypes[i], OptionalNone, false, 0, "r", false, iter, false,
+                                          metaData, patchParams);
             }
             out << nl << "return r;";
         }
@@ -1409,7 +1410,7 @@ FreezeGenerator::generate(UnitPtr& u, const Index& index)
     out << nl << "IceInternal.BasicStream __os = "
         << "new IceInternal.BasicStream(IceInternal.Util.getInstance(communicator()), encoding(), true, false);";
     int iter = 0;
-    writeMarshalUnmarshalCode(out, "", dataMember->type(), OptionalNone, 0, valueS, true, iter, false);
+    writeMarshalUnmarshalCode(out, "", dataMember->type(), OptionalNone, false, 0, valueS, true, iter, false);
     if(type->usesClasses())
     {
         out << nl << "__os.writePendingObjects();";
diff --git a/cpp/src/slice2java/Gen.cpp b/cpp/src/slice2java/Gen.cpp
index 37879c13ca7..1327e24fb14 100644
--- a/cpp/src/slice2java/Gen.cpp
+++ b/cpp/src/slice2java/Gen.cpp
@@ -109,16 +109,23 @@ Slice::JavaVisitor::~JavaVisitor()
 }
 
 vector<string>
-Slice::JavaVisitor::getParams(const OperationPtr& op, const string& package)
+Slice::JavaVisitor::getParams(const OperationPtr& op, const string& package, bool local)
 {
     vector<string> params;
 
+    const bool optionalMapping = useOptionalMapping(op);
+
     ParamDeclList paramList = op->parameters();
     for(ParamDeclList::const_iterator q = paramList.begin(); q != paramList.end(); ++q)
     {
         StringList metaData = (*q)->getMetaData();
+        bool optional = (*q)->optional();
+        if(optional && (local || (*q)->isOutParam()))
+        {
+            optional = optionalMapping;
+        }
         string typeString = typeToString((*q)->type(), (*q)->isOutParam() ? TypeModeOut : TypeModeIn, package,
-                                         metaData, true, (*q)->optional());
+                                         metaData, true, optional);
         params.push_back(typeString + ' ' + fixKwd((*q)->name()));
     }
 
@@ -130,12 +137,24 @@ Slice::JavaVisitor::getParamsProxy(const OperationPtr& op, const string& package
 {
     vector<string> params;
 
+    const bool optionalMapping = useOptionalMapping(op);
+
     ParamDeclList paramList = op->parameters();
     for(ParamDeclList::const_iterator q = paramList.begin(); q != paramList.end(); ++q)
     {
+        bool optional;
+        if((*q)->optional())
+        {
+            optional = (*q)->isOutParam() ? true : optionalMapping;
+        }
+        else
+        {
+            optional = false;
+        }
+
         StringList metaData = (*q)->getMetaData();
         string typeString = typeToString((*q)->type(), (*q)->isOutParam() ? TypeModeOut : TypeModeIn, package,
-                                         metaData, true, useOptionalMapping(*q));
+                                         metaData, true, optional);
         if(final)
         {
             typeString = "final " + typeString;
@@ -151,15 +170,28 @@ Slice::JavaVisitor::getInOutParams(const OperationPtr& op, const string& package
 {
     vector<string> params;
 
+    const bool optionalMapping = useOptionalMapping(op);
+
     ParamDeclList paramList = op->parameters();
     for(ParamDeclList::const_iterator q = paramList.begin(); q != paramList.end(); ++q)
     {
         if((*q)->isOutParam() == (paramType == OutParam))
         {
-            bool optional = (*q)->optional();
-            if(optional && proxy)
+            bool optional;
+            if((*q)->optional())
             {
-                optional = useOptionalMapping(*q);
+                if(proxy)
+                {
+                    optional = paramType == InParam ? optionalMapping : true;
+                }
+                else
+                {
+                    optional = true;
+                }
+            }
+            else
+            {
+                optional = false;
             }
             StringList metaData = (*q)->getMetaData();
             string typeString = typeToString((*q)->type(), paramType == InParam ? TypeModeIn : TypeModeOut, package,
@@ -186,14 +218,17 @@ Slice::JavaVisitor::getParamsAsync(const OperationPtr& op, const string& package
 }
 
 vector<string>
-Slice::JavaVisitor::getParamsAsyncCB(const OperationPtr& op, const string& package)
+Slice::JavaVisitor::getParamsAsyncCB(const OperationPtr& op, const string& package, bool amd)
 {
     vector<string> params;
 
+    const bool optionalMapping = amd ? useOptionalMapping(op) : true;
+
     TypePtr ret = op->returnType();
     if(ret)
     {
-        string retS = typeToString(ret, TypeModeIn, package, op->getMetaData(), true, op->returnIsOptional());
+        string retS = typeToString(ret, TypeModeIn, package, op->getMetaData(), true,
+                                   optionalMapping && op->returnIsOptional());
         params.push_back(retS + " __ret");
     }
 
@@ -203,7 +238,7 @@ Slice::JavaVisitor::getParamsAsyncCB(const OperationPtr& op, const string& packa
         if((*q)->isOutParam())
         {
             string typeString = typeToString((*q)->type(), TypeModeIn, package, (*q)->getMetaData(), true,
-                                             (*q)->optional());
+                                             optionalMapping && (*q)->optional());
             params.push_back(typeString + ' ' + fixKwd((*q)->name()));
         }
     }
@@ -291,7 +326,8 @@ Slice::JavaVisitor::getArgsAsyncCB(const OperationPtr& op)
 
 void
 Slice::JavaVisitor::writeMarshalUnmarshalParams(Output& out, const string& package, const ParamDeclList& params,
-                                                const OperationPtr& op, int& iter, bool marshal, bool dispatch)
+                                                const OperationPtr& op, int& iter, bool marshal, bool optionalMapping,
+                                                bool dispatch)
 {
     ParamDeclList optionals;
     ParamDeclList::const_iterator pli;
@@ -311,8 +347,8 @@ Slice::JavaVisitor::writeMarshalUnmarshalParams(Output& out, const string& packa
             {
                 patchParams = paramName;
             }
-            writeMarshalUnmarshalCode(out, package, (*pli)->type(), OptionalNone, 0, paramName, marshal, iter, holder,
-                                      (*pli)->getMetaData(), patchParams);
+            writeMarshalUnmarshalCode(out, package, (*pli)->type(), OptionalNone, false, 0, paramName, marshal,
+                                      iter, holder, (*pli)->getMetaData(), patchParams);
         }
     }
 
@@ -325,13 +361,14 @@ Slice::JavaVisitor::writeMarshalUnmarshalParams(Output& out, const string& packa
         BuiltinPtr builtin = BuiltinPtr::dynamicCast(ret);
         ClassDeclPtr cl = ClassDeclPtr::dynamicCast(ret);
         returnsObject = (builtin && builtin->kind() == Builtin::KindObject) || cl;
+        const bool optional = optionalMapping && op->returnIsOptional();
 
-        string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true, op->returnIsOptional());
+        string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true, optional);
         bool holder = false;
 
         if(!marshal)
         {
-            if(op->returnIsOptional())
+            if(optional)
             {
                 out << nl << retS << " __ret = new " << retS << "();";
             }
@@ -348,7 +385,7 @@ Slice::JavaVisitor::writeMarshalUnmarshalParams(Output& out, const string& packa
 
         if(!op->returnIsOptional())
         {
-            writeMarshalUnmarshalCode(out, package, ret, OptionalNone, 0, "__ret", marshal, iter, holder,
+            writeMarshalUnmarshalCode(out, package, ret, OptionalNone, false, 0, "__ret", marshal, iter, holder,
                                       op->getMetaData());
         }
     }
@@ -375,29 +412,22 @@ Slice::JavaVisitor::writeMarshalUnmarshalParams(Output& out, const string& packa
     {
         if(checkReturnType && op->returnTag() < (*pli)->tag())
         {
-            writeMarshalUnmarshalCode(out, package, ret, OptionalReturnParam, op->returnTag(), "__ret", marshal, iter,
-                                      false, op->getMetaData());
+            writeMarshalUnmarshalCode(out, package, ret, OptionalReturnParam, optionalMapping, op->returnTag(),
+                                      "__ret", marshal, iter, false, op->getMetaData());
             checkReturnType = false;
         }
 
-        OptionalMode mode;
-        if((*pli)->isOutParam())
-        {
-            mode = OptionalOutParam;
-        }
-        else
-        {
-            mode = useOptionalMapping(*pli) ? OptionalInParamOpt : OptionalInParamReq;
-        }
+        const bool holder = dispatch && (*pli)->isOutParam() && !optionalMapping;
 
-        writeMarshalUnmarshalCode(out, package, (*pli)->type(), mode, (*pli)->tag(), fixKwd((*pli)->name()), marshal,
-                                  iter, false, (*pli)->getMetaData());
+        writeMarshalUnmarshalCode(out, package, (*pli)->type(),
+                                  (*pli)->isOutParam() ? OptionalOutParam : OptionalInParam, optionalMapping,
+                                  (*pli)->tag(), fixKwd((*pli)->name()), marshal, iter, holder, (*pli)->getMetaData());
     }
 
     if(checkReturnType)
     {
-        writeMarshalUnmarshalCode(out, package, ret, OptionalReturnParam, op->returnTag(), "__ret", marshal, iter,
-                                  false, op->getMetaData());
+        writeMarshalUnmarshalCode(out, package, ret, OptionalReturnParam, optionalMapping, op->returnTag(), "__ret",
+                                  marshal, iter, false, op->getMetaData());
     }
 }
 
@@ -554,16 +584,16 @@ Slice::JavaVisitor::writeMarshalDataMember(Output& out, const string& package, c
 {
     if(!member->optional())
     {
-        writeMarshalUnmarshalCode(out, package, member->type(), OptionalNone, 0, fixKwd(member->name()), true, iter,
-                                  false, member->getMetaData());
+        writeMarshalUnmarshalCode(out, package, member->type(), OptionalNone, false, 0, fixKwd(member->name()),
+                                  true, iter, false, member->getMetaData());
     }
     else
     {
         out << nl << "if(__has_" << member->name() << " && __os.writeOpt(" << member->tag() << ", "
             << getOptionalType(member->type()) << "))";
         out << sb;
-        writeMarshalUnmarshalCode(out, package, member->type(), OptionalMember, 0, fixKwd(member->name()), true, iter,
-                                  false, member->getMetaData());
+        writeMarshalUnmarshalCode(out, package, member->type(), OptionalMember, false, 0, fixKwd(member->name()), true,
+                                  iter, false, member->getMetaData());
         out << eb;
     }
 }
@@ -586,15 +616,15 @@ Slice::JavaVisitor::writeUnmarshalDataMember(Output& out, const string& package,
 
     if(!member->optional())
     {
-        writeMarshalUnmarshalCode(out, package, member->type(), OptionalNone, 0, fixKwd(member->name()), false, iter,
-                                  false, member->getMetaData(), patchParams);
+        writeMarshalUnmarshalCode(out, package, member->type(), OptionalNone, false, 0, fixKwd(member->name()), false,
+                                  iter, false, member->getMetaData(), patchParams);
     }
     else
     {
         out << nl << "if(__has_" << member->name() << " = __is.readOpt(" << member->tag() << ", "
             << getOptionalType(member->type()) << "))";
         out << sb;
-        writeMarshalUnmarshalCode(out, package, member->type(), OptionalMember, 0, fixKwd(member->name()), false,
+        writeMarshalUnmarshalCode(out, package, member->type(), OptionalMember, false, 0, fixKwd(member->name()), false,
                                   iter, false, member->getMetaData(), patchParams);
         out << eb;
     }
@@ -880,7 +910,8 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
 
         string deprecateReason = getDeprecateReason(op, cl, "operation");
 
-        bool amd = cl->hasMetaData("amd") || op->hasMetaData("amd");
+        const bool amd = cl->hasMetaData("amd") || op->hasMetaData("amd");
+        const bool optionalMapping = useOptionalMapping(op);
 
         vector<string> params;
         vector<string> args;
@@ -962,7 +993,8 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
                 writeDocComment(out, op, deprecateReason);
             }
             out << nl << "public final "
-                << typeToString(ret, TypeModeReturn, package, op->getMetaData(), true, op->returnIsOptional())
+                << typeToString(ret, TypeModeReturn, package, op->getMetaData(), true,
+                                optionalMapping && op->returnIsOptional())
                 << nl << opName << spar << params << epar;
             if(op->hasMetaData("UserException"))
             {
@@ -1009,7 +1041,9 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
             << " __obj, IceInternal.Incoming __inS, Ice.Current __current)";
         out << sb;
 
-        bool amd = cl->hasMetaData("amd") || op->hasMetaData("amd");
+        const bool amd = cl->hasMetaData("amd") || op->hasMetaData("amd");
+        const bool optionalMapping = useOptionalMapping(op);
+
         if(!amd)
         {
             TypePtr ret = op->returnType();
@@ -1080,7 +1114,7 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
                     }
                 }
                 iter = 0;
-                writeMarshalUnmarshalParams(out, package, inParams, 0, iter, false, true);
+                writeMarshalUnmarshalParams(out, package, inParams, 0, iter, false, true, true);
                 out << nl << "__inS.endReadParams();";
             }
             else
@@ -1094,7 +1128,7 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
             for(pli = outParams.begin(); pli != outParams.end(); ++pli)
             {
                 string typeS = typeToString((*pli)->type(), TypeModeOut, package, (*pli)->getMetaData(), true,
-                                            (*pli)->optional());
+                                            optionalMapping && (*pli)->optional());
                 out << nl << typeS << ' ' << fixKwd((*pli)->name()) << " = new " << typeS << "();";
             }
 
@@ -1109,7 +1143,8 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
             out << nl;
             if(ret)
             {
-                string retS = typeToString(ret, TypeModeReturn, package, opMetaData, true, op->returnIsOptional());
+                string retS = typeToString(ret, TypeModeReturn, package, opMetaData, true,
+                                           optionalMapping && op->returnIsOptional());
                 out << retS << " __ret = ";
             }
             out << "__obj." << fixKwd(opName) << '(';
@@ -1144,7 +1179,7 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
                 {
                     out << nl << "__os.format(" << formatTypeToString(format) << ");";
                 }
-                writeMarshalUnmarshalParams(out, package, outParams, op, iter, true, true);
+                writeMarshalUnmarshalParams(out, package, outParams, op, iter, true, optionalMapping, true);
                 out << nl << "__inS.__endWriteParams(true);";
             }
             else
@@ -1205,24 +1240,28 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
                 iter = 0;
                 for(pli = inParams.begin(); pli != inParams.end(); ++pli)
                 {
-                    StringList metaData = (*pli)->getMetaData();
                     TypePtr paramType = (*pli)->type();
                     string paramName = fixKwd((*pli)->name());
-                    string typeS = typeToString(paramType, TypeModeIn, package, metaData);
-                    BuiltinPtr builtin = BuiltinPtr::dynamicCast(paramType);
-                    if((builtin && builtin->kind() == Builtin::KindObject) || ClassDeclPtr::dynamicCast(paramType))
+                    string typeS = typeToString(paramType, TypeModeIn, package, (*pli)->getMetaData(),
+                                                true, (*pli)->optional());
+                    if((*pli)->optional())
                     {
-                        out << nl << typeS << "Holder " << paramName << " = new " << typeS << "Holder();";
-                        writeMarshalUnmarshalCode(out, package, paramType, OptionalNone, 0, paramName, false, iter,
-                                                  true, metaData, string());
+                        out << nl << typeS << ' ' << paramName << " = new " << typeS << "();";
                     }
                     else
                     {
-                        out << nl << typeS << ' ' << paramName << ';';
-                        writeMarshalUnmarshalCode(out, package, paramType, OptionalNone, 0, paramName, false, iter,
-                                                  false, metaData);
+                        BuiltinPtr builtin = BuiltinPtr::dynamicCast(paramType);
+                        if((builtin && builtin->kind() == Builtin::KindObject) || ClassDeclPtr::dynamicCast(paramType))
+                        {
+                            out << nl << typeS << "Holder " << paramName << " = new " << typeS << "Holder();";
+                        }
+                        else
+                        {
+                            out << nl << typeS << ' ' << paramName << ';';
+                        }
                     }
                 }
+                writeMarshalUnmarshalParams(out, package, inParams, 0, iter, false, true, true);
                 out << nl << "__inS.endReadParams();";
             }
             else
@@ -1243,10 +1282,13 @@ Slice::JavaVisitor::writeDispatchAndMarshalling(Output& out, const ClassDefPtr&
             {
                 TypePtr paramType = (*pli)->type();
                 out << fixKwd((*pli)->name());
-                BuiltinPtr builtin = BuiltinPtr::dynamicCast(paramType);
-                if((builtin && builtin->kind() == Builtin::KindObject) || ClassDeclPtr::dynamicCast(paramType))
+                if(!(*pli)->optional())
                 {
-                    out << ".value";
+                    BuiltinPtr builtin = BuiltinPtr::dynamicCast(paramType);
+                    if((builtin && builtin->kind() == Builtin::KindObject) || ClassDeclPtr::dynamicCast(paramType))
+                    {
+                        out << ".value";
+                    }
                 }
                 out << ", ";
             }
@@ -2357,7 +2399,8 @@ Slice::Gen::OpsVisitor::writeOperations(const ClassDefPtr& p, bool noCurrent)
         TypePtr ret;
         vector<string> params;
 
-        bool amd = !p->isLocal() && (cl->hasMetaData("amd") || op->hasMetaData("amd"));
+        const bool amd = !p->isLocal() && (cl->hasMetaData("amd") || op->hasMetaData("amd"));
+        const bool optionalMapping = useOptionalMapping(op);
 
         if(amd)
         {
@@ -2369,7 +2412,8 @@ Slice::Gen::OpsVisitor::writeOperations(const ClassDefPtr& p, bool noCurrent)
             ret = op->returnType();
         }
 
-        string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true, op->returnIsOptional());
+        string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true,
+                                   optionalMapping && op->returnIsOptional());
         ExceptionList throws = op->throws();
         throws.sort();
         throws.unique();
@@ -2528,7 +2572,9 @@ Slice::Gen::TieVisitor::visitClassDefStart(const ClassDefPtr& p)
     {
         ContainerPtr container = (*r)->container();
         ClassDefPtr cl = ClassDefPtr::dynamicCast(container);
-        bool hasAMD = cl->hasMetaData("amd") || (*r)->hasMetaData("amd");
+        const bool hasAMD = cl->hasMetaData("amd") || (*r)->hasMetaData("amd");
+        const bool optionalMapping = useOptionalMapping(*r);
+
 #if defined(__SUNPRO_CC) && (__SUNPRO_CC==0x550)
         //
         // Work around for Sun CC 5.5 bug #4853566
@@ -2545,8 +2591,10 @@ Slice::Gen::TieVisitor::visitClassDefStart(const ClassDefPtr& p)
 #else
         string opName = hasAMD ? (*r)->name() + "_async" : fixKwd((*r)->name());
 #endif
+
         TypePtr ret = (*r)->returnType();
-        string retS = typeToString(ret, TypeModeReturn, package, (*r)->getMetaData());
+        string retS = typeToString(ret, TypeModeReturn, package, (*r)->getMetaData(), true,
+                                   optionalMapping && (*r)->returnIsOptional());
 
         vector<string> params;
         vector<string> args;
@@ -2780,7 +2828,7 @@ Slice::Gen::TypesVisitor::visitClassDefStart(const ClassDefPtr& p)
 
     //
     // For local classes and interfaces, we don't use the OperationsNC interface.
-    // Instead, we generated the operation signatures directly into the class
+    // Instead, we generate the operation signatures directly into the class
     // or interface.
     //
     if(p->isLocal())
@@ -2793,12 +2841,13 @@ Slice::Gen::TypesVisitor::visitClassDefStart(const ClassDefPtr& p)
             ContainerPtr container = op->container();
             ClassDefPtr cl = ClassDefPtr::dynamicCast(container);
             string opname = op->name();
+            const bool optionalMapping = useOptionalMapping(op);
 
-            TypePtr ret;
-            vector<string> params = getParams(op, package);
-            ret = op->returnType();
+            TypePtr ret = op->returnType();
+            vector<string> params = getParams(op, package, true);
 
-            string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData());
+            string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true,
+                                       optionalMapping && op->returnIsOptional());
             ExceptionList throws = op->throws();
             throws.sort();
             throws.unique();
@@ -4418,6 +4467,8 @@ Slice::Gen::HelperVisitor::visitClassDefStart(const ClassDefPtr& p)
         vector<string> params = getParamsProxy(op, package);
         vector<string> args = getArgs(op);
 
+        const bool optionalMapping = useOptionalMapping(op);
+
         ExceptionList throws = op->throws();
         throws.sort();
         throws.unique();
@@ -4615,7 +4666,7 @@ Slice::Gen::HelperVisitor::visitClassDefStart(const ClassDefPtr& p)
                         pl.push_back(*pli);
                     }
                 }
-                writeMarshalUnmarshalParams(out, package, pl, 0, iter, true);
+                writeMarshalUnmarshalParams(out, package, pl, 0, iter, true, optionalMapping);
                 out << nl << "__result.__endWriteParams();";
             }
             else
@@ -4688,7 +4739,7 @@ Slice::Gen::HelperVisitor::visitClassDefStart(const ClassDefPtr& p)
                             pl.push_back(*pli);
                         }
                     }
-                    writeMarshalUnmarshalParams(out, package, pl, op, iter, false);
+                    writeMarshalUnmarshalParams(out, package, pl, op, iter, false, true);
                     out << nl << "__result.__endReadParams();";
                 }
                 else
@@ -5562,6 +5613,7 @@ Slice::Gen::DelegateMVisitor::visitClassDefStart(const ClassDefPtr& p)
         string opName = fixKwd(op->name());
         TypePtr ret = op->returnType();
         string retS = typeToString(ret, TypeModeReturn, package, opMetaData, true, op->returnIsOptional());
+        const bool optionalMapping = useOptionalMapping(op);
         int iter = 0;
 
         ParamDeclList inParams;
@@ -5617,7 +5669,7 @@ Slice::Gen::DelegateMVisitor::visitClassDefStart(const ClassDefPtr& p)
             {
                 out << nl << "__os.format(" << formatTypeToString(format) << ");";
             }
-            writeMarshalUnmarshalParams(out, package, inParams, 0, iter, true);
+            writeMarshalUnmarshalParams(out, package, inParams, 0, iter, true, optionalMapping);
             out << nl << "__og.endWriteParams();";
             out << eb;
             out << nl << "catch(Ice.LocalException __ex)";
@@ -5660,7 +5712,7 @@ Slice::Gen::DelegateMVisitor::visitClassDefStart(const ClassDefPtr& p)
         if(ret || !outParams.empty())
         {
             out << nl << "IceInternal.BasicStream __is = __og.startReadParams();";
-            writeMarshalUnmarshalParams(out, package, outParams, op, iter, false);
+            writeMarshalUnmarshalParams(out, package, outParams, op, iter, false, true);
             out << nl << "__og.endReadParams();";
         }
         else
@@ -5742,6 +5794,7 @@ Slice::Gen::DelegateDVisitor::visitClassDefStart(const ClassDefPtr& p)
         ClassDefPtr cl = ClassDefPtr::dynamicCast(container);
         string opName = fixKwd(op->name());
         TypePtr ret = op->returnType();
+        const bool optionalMapping = useOptionalMapping(op);
         string retS = typeToString(ret, TypeModeReturn, package, op->getMetaData(), true, op->returnIsOptional());
 
         ExceptionList throws = op->throws();
@@ -5763,25 +5816,6 @@ Slice::Gen::DelegateDVisitor::visitClassDefStart(const ClassDefPtr& p)
 
         vector<string> params = getParamsProxy(op, package, true);
 
-        //
-        // Collect the arguments that will be passed to the servant.
-        //
-        // Note that for optional in parameters, we may have to wrap a value
-        // in an Optional object to be compatible with the servant's signature.
-        //
-        vector<string> args;
-        ParamDeclList paramList = op->parameters();
-        for(ParamDeclList::const_iterator q = paramList.begin(); q != paramList.end(); ++q)
-        {
-            string param = fixKwd((*q)->name());
-            if(!(*q)->isOutParam() && (*q)->optional() && !useOptionalMapping(*q))
-            {
-                string typeString = typeToString((*q)->type(), TypeModeIn, package, (*q)->getMetaData(), true, true);
-                param = "new " + typeString + "(" + param + ")";
-            }
-            args.push_back(param);
-        }
-
         out << sp;
         if(!deprecateReason.empty())
         {
@@ -5837,27 +5871,87 @@ Slice::Gen::DelegateDVisitor::visitClassDefStart(const ClassDefPtr& p)
                 out << sb;
             }
 
+            //
+            // Collect the arguments that will be passed to the servant.
+            //
+            vector<string> args;
+            ParamDeclList paramList = op->parameters();
+            ParamDeclList::const_iterator q;
+            for(q = paramList.begin(); q != paramList.end(); ++q)
+            {
+                string param = fixKwd((*q)->name());
+                //
+                // For optional parameters, the proxy mapping can differ from the servant
+                // mapping, depending on whether the optional mapping is being used.
+                //
+                if((*q)->optional() && !optionalMapping)
+                {
+                    if((*q)->isOutParam())
+                    {
+                        param = "__" + (*q)->name();
+                        string typeS = typeToString((*q)->type(), TypeModeOut, package, (*q)->getMetaData());
+                        out << nl << typeS << ' ' << param << " = new " << typeS << "();";
+                    }
+                    else
+                    {
+                        string typeS = typeToString((*q)->type(), TypeModeIn, package, (*q)->getMetaData(), true, true);
+                        param = "new " + typeS + "(" + param + ")";
+                    }
+                }
+                args.push_back(param);
+            }
+
             out << nl;
             if(ret)
             {
                 if(op->returnIsOptional())
                 {
-                    out << resultType << " __r = ";
+                    if(optionalMapping)
+                    {
+                        out << resultType << " __r = ";
+                    }
+                    else
+                    {
+                        out << typeToString(ret, TypeModeIn, package, op->getMetaData()) << " __r = ";
+                    }
                 }
                 else
                 {
                     out << "__result.value = ";
                 }
             }
+
             out << "__servant." << opName << spar << args << "__current" << epar << ';';
-            if(op->returnIsOptional())
+
+            for(q = paramList.begin(); q != paramList.end(); ++q)
             {
-                out << nl << "if(__r != null && __r.isSet())";
-                out << sb;
-                out << nl << "__result.set(__r.get());";
-                out << eb;
+                //
+                // For optional parameters, the proxy mapping can differ from the servant
+                // mapping, depending on whether the optional mapping is being used.
+                //
+                if((*q)->optional() && !optionalMapping && (*q)->isOutParam())
+                {
+                    out << nl << fixKwd((*q)->name()) << ".set(__" << (*q)->name() << ".value);";
+                }
+            }
+
+            if(ret && op->returnIsOptional())
+            {
+                if(optionalMapping)
+                {
+                    out << nl << "if(__r != null && __r.isSet())";
+                    out << sb;
+                    out << nl << "__result.set(__r.get());";
+                    out << eb;
+                }
+                else
+                {
+                    out << nl << "__result.set(__r);";
+                }
             }
+
             out << nl << "return Ice.DispatchStatus.DispatchOK;";
+
             if(!throws.empty())
             {
                 out << eb;
@@ -5991,129 +6085,144 @@ Slice::Gen::BaseImplVisitor::BaseImplVisitor(const string& dir) :
 
 void
 Slice::Gen::BaseImplVisitor::writeDecl(Output& out, const string& package, const string& name, const TypePtr& type,
-                                       const StringList& metaData)
+                                       const StringList& metaData, bool optional)
 {
-    out << nl << typeToString(type, TypeModeIn, package, metaData) << ' ' << name;
+    string typeS = typeToString(type, TypeModeIn, package, metaData, true, optional);
+    out << nl << typeS << ' ' << name;
 
-    BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
-    if(builtin)
+    if(optional)
     {
-        switch(builtin->kind())
+        out << " = new " << typeS << "();";
+    }
+    else
+    {
+        BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
+        if(builtin)
         {
-            case Builtin::KindBool:
-            {
-                out << " = false";
-                break;
-            }
-            case Builtin::KindByte:
-            {
-                out << " = (byte)0";
-                break;
-            }
-            case Builtin::KindShort:
+            switch(builtin->kind())
             {
-                out << " = (short)0";
-                break;
-            }
-            case Builtin::KindInt:
-            case Builtin::KindLong:
-            {
-                out << " = 0";
-                break;
-            }
-            case Builtin::KindFloat:
-            {
-                out << " = (float)0.0";
-                break;
-            }
-            case Builtin::KindDouble:
-            {
-                out << " = 0.0";
-                break;
+                case Builtin::KindBool:
+                {
+                    out << " = false";
+                    break;
+                }
+                case Builtin::KindByte:
+                {
+                    out << " = (byte)0";
+                    break;
+                }
+                case Builtin::KindShort:
+                {
+                    out << " = (short)0";
+                    break;
+                }
+                case Builtin::KindInt:
+                case Builtin::KindLong:
+                {
+                    out << " = 0";
+                    break;
+                }
+                case Builtin::KindFloat:
+                {
+                    out << " = (float)0.0";
+                    break;
+                }
+                case Builtin::KindDouble:
+                {
+                    out << " = 0.0";
+                    break;
+                }
+                case Builtin::KindString:
+                {
+                    out << " = \"\"";
+                    break;
+                }
+                case Builtin::KindObject:
+                case Builtin::KindObjectProxy:
+                case Builtin::KindLocalObject:
+                {
+                    out << " = null";
+                    break;
+                }
             }
-            case Builtin::KindString:
+        }
+        else
+        {
+            EnumPtr en = EnumPtr::dynamicCast(type);
+            if(en)
             {
-                out << " = \"\"";
-                break;
+                EnumeratorList enumerators = en->getEnumerators();
+                out << " = " << getAbsolute(en, package) << '.' << fixKwd(enumerators.front()->name());
             }
-            case Builtin::KindObject:
-            case Builtin::KindObjectProxy:
-            case Builtin::KindLocalObject:
+            else
             {
                 out << " = null";
-                break;
             }
         }
-    }
-    else
-    {
-        EnumPtr en = EnumPtr::dynamicCast(type);
-        if(en)
-        {
-            EnumeratorList enumerators = en->getEnumerators();
-            out << " = " << getAbsolute(en, package) << '.' << fixKwd(enumerators.front()->name());
-        }
-        else
-        {
-            out << " = null";
-        }
-    }
 
-    out << ';';
+        out << ';';
+    }
 }
 
 void
-Slice::Gen::BaseImplVisitor::writeReturn(Output& out, const TypePtr& type)
+Slice::Gen::BaseImplVisitor::writeReturn(Output& out, const TypePtr& type, bool optional)
 {
-    BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
-    if(builtin)
+    if(optional)
     {
-        switch(builtin->kind())
+        out << nl << "return null;";
+    }
+    else
+    {
+        BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
+        if(builtin)
         {
-            case Builtin::KindBool:
-            {
-                out << nl << "return false;";
-                break;
-            }
-            case Builtin::KindByte:
+            switch(builtin->kind())
             {
-                out << nl << "return (byte)0;";
-                break;
-            }
-            case Builtin::KindShort:
-            {
-                out << nl << "return (short)0;";
-                break;
-            }
-            case Builtin::KindInt:
-            case Builtin::KindLong:
-            {
-                out << nl << "return 0;";
-                break;
-            }
-            case Builtin::KindFloat:
-            {
-                out << nl << "return (float)0.0;";
-                break;
-            }
-            case Builtin::KindDouble:
-            {
-                out << nl << "return 0.0;";
-                break;
-            }
-            case Builtin::KindString:
-            case Builtin::KindObject:
-            case Builtin::KindObjectProxy:
-            case Builtin::KindLocalObject:
-            {
-                out << nl << "return null;";
-                break;
+                case Builtin::KindBool:
+                {
+                    out << nl << "return false;";
+                    break;
+                }
+                case Builtin::KindByte:
+                {
+                    out << nl << "return (byte)0;";
+                    break;
+                }
+                case Builtin::KindShort:
+                {
+                    out << nl << "return (short)0;";
+                    break;
+                }
+                case Builtin::KindInt:
+                case Builtin::KindLong:
+                {
+                    out << nl << "return 0;";
+                    break;
+                }
+                case Builtin::KindFloat:
+                {
+                    out << nl << "return (float)0.0;";
+                    break;
+                }
+                case Builtin::KindDouble:
+                {
+                    out << nl << "return 0.0;";
+                    break;
+                }
+                case Builtin::KindString:
+                case Builtin::KindObject:
+                case Builtin::KindObjectProxy:
+                case Builtin::KindLocalObject:
+                {
+                    out << nl << "return null;";
+                    break;
+                }
             }
+            return;
         }
-        return;
-    }
 
-    out << nl << "return null;";
+        out << nl << "return null;";
+    }
 }
 
 void
@@ -6122,8 +6231,10 @@ Slice::Gen::BaseImplVisitor::writeOperation(Output& out, const string& package,
     string opName = op->name();
 
     TypePtr ret = op->returnType();
+    const bool optionalMapping = useOptionalMapping(op);
     StringList opMetaData = op->getMetaData();
-    string retS = typeToString(ret, TypeModeReturn, package, opMetaData);
+    string retS = typeToString(ret, TypeModeReturn, package, opMetaData, true,
+                               optionalMapping && op->returnIsOptional());
     vector<string> params = getParams(op, package);
 
     ContainerPtr container = op->container();
@@ -6168,13 +6279,14 @@ Slice::Gen::BaseImplVisitor::writeOperation(Output& out, const string& package,
         }
         if(ret)
         {
-            writeDecl(out, package, result, ret, opMetaData);
+            writeDecl(out, package, result, ret, opMetaData, optionalMapping && op->returnIsOptional());
         }
         for(q = paramList.begin(); q != paramList.end(); ++q)
         {
             if((*q)->isOutParam())
             {
-                writeDecl(out, package, fixKwd((*q)->name()), (*q)->type(), (*q)->getMetaData());
+                writeDecl(out, package, fixKwd((*q)->name()), (*q)->type(), (*q)->getMetaData(),
+                          optionalMapping && (*q)->optional());
             }
         }
 
@@ -6231,7 +6343,7 @@ Slice::Gen::BaseImplVisitor::writeOperation(Output& out, const string& package,
         //
         if(ret)
         {
-            writeReturn(out, ret);
+            writeReturn(out, ret, optionalMapping && op->returnIsOptional());
         }
 
         out << eb;
@@ -6432,7 +6544,7 @@ Slice::Gen::AsyncVisitor::visitOperation(const OperationPtr& p)
 
         ExceptionList throws = p->throws();
 
-        vector<string> params = getParamsAsyncCB(p, classPkg);
+        vector<string> params = getParamsAsyncCB(p, classPkg, false);
         vector<string> args = getInOutArgs(p, OutParam);
 
         writeDocCommentOp(out, p);
@@ -6529,7 +6641,7 @@ Slice::Gen::AsyncVisitor::visitOperation(const OperationPtr& p)
 
         ExceptionList throws = p->throws();
 
-        vector<string> params = getParamsAsyncCB(p, classPkg);
+        vector<string> params = getParamsAsyncCB(p, classPkg, false);
         vector<string> args = getInOutArgs(p, OutParam);
 
         writeDocCommentOp(out, p);
@@ -6596,7 +6708,9 @@ Slice::Gen::AsyncVisitor::visitOperation(const OperationPtr& p)
         string classNameAMDI = "_AMD_" + cl->name();
         string absoluteAMDI = getAbsolute(cl, "", "_AMD_", "_" + name);
 
-        vector<string> paramsAMD = getParamsAsyncCB(p, classPkg);
+        vector<string> paramsAMD = getParamsAsyncCB(p, classPkg, true);
+
+        const bool optionalMapping = useOptionalMapping(p);
 
         {
             open(absoluteAMD, p->file());
@@ -6676,19 +6790,7 @@ Slice::Gen::AsyncVisitor::visitOperation(const OperationPtr& p)
                 {
                     out << nl << "__os.format(" << formatTypeToString(format) << ");";
                 }
-                for(pli = outParams.begin(); pli != outParams.end(); ++pli)
-                {
-                    StringList metaData = (*pli)->getMetaData();
-                    string typeS = typeToString((*pli)->type(), TypeModeIn, classPkg, metaData);
-                    writeMarshalUnmarshalCode(out, classPkg, (*pli)->type(), OptionalNone, 0, fixKwd((*pli)->name()),
-                                              true, iter, false, metaData);
-                }
-                if(ret)
-                {
-                    string retS = typeToString(ret, TypeModeIn, classPkg, opMetaData);
-                    writeMarshalUnmarshalCode(out, classPkg, ret, OptionalNone, 0, "__ret", true, iter, false,
-                                              opMetaData);
-                }
+                writeMarshalUnmarshalParams(out, classPkg, outParams, p, iter, true, optionalMapping, false);
                 out << nl << "this.__endWriteParams(true);";
                 out << eb;
                 out << nl << "catch(Ice.LocalException __ex)";
diff --git a/cpp/src/slice2java/Gen.h b/cpp/src/slice2java/Gen.h
index 5cfeae3714a..94f0dc95a2d 100644
--- a/cpp/src/slice2java/Gen.h
+++ b/cpp/src/slice2java/Gen.h
@@ -32,11 +32,11 @@ protected:
     //
     // Compose the parameter lists for an operation.
     //
-    std::vector<std::string> getParams(const OperationPtr&, const std::string&);
+    std::vector<std::string> getParams(const OperationPtr&, const std::string&, bool = false);
     std::vector<std::string> getParamsProxy(const OperationPtr&, const std::string&, bool = false);
     std::vector<std::string> getInOutParams(const OperationPtr&, const std::string&, ParamDir, bool);
     std::vector<std::string> getParamsAsync(const OperationPtr&, const std::string&, bool);
-    std::vector<std::string> getParamsAsyncCB(const OperationPtr&, const std::string&);
+    std::vector<std::string> getParamsAsyncCB(const OperationPtr&, const std::string&, bool);
 
     //
     // Compose the argument lists for an operation.
@@ -47,7 +47,7 @@ protected:
     std::vector<std::string> getArgsAsyncCB(const OperationPtr&);
 
     void writeMarshalUnmarshalParams(::IceUtilInternal::Output&, const std::string&, const ParamDeclList&,
-                                     const OperationPtr&, int&, bool, bool = false);
+                                     const OperationPtr&, int&, bool, bool, bool = false);
 
     //
     // Generate a throws clause containing only non-local exceptions.
@@ -290,12 +290,13 @@ private:
         // Generate code to emit a local variable declaration and initialize it
         // if necessary.
         //
-        void writeDecl(::IceUtilInternal::Output&, const std::string&, const std::string&, const TypePtr&, const StringList&);
+        void writeDecl(::IceUtilInternal::Output&, const std::string&, const std::string&, const TypePtr&,
+                       const StringList&, bool);
 
         //
         // Generate code to return a value.
         //
-        void writeReturn(::IceUtilInternal::Output&, const TypePtr&);
+        void writeReturn(::IceUtilInternal::Output&, const TypePtr&, bool);
 
         //
         // Generate an operation.