diff --git a/proto/compiler/README.md b/proto/compiler/README.md
index 2ba1d1c433e..1deeebe1ffa 100644
--- a/proto/compiler/README.md
+++ b/proto/compiler/README.md
@@ -22,7 +22,7 @@ In folder /src/ you can find sources for ProtoKot-runtime, that will be used by
 ## Using generated code
 
 Example:
-
+    
     // Messages work only with CodedStream classes, provided by ProtoKot-runtime library.
     // One can create CodedStream passing any instance of corresponding Stream from Java's library.
     val s = ByteArrayOutputStream()
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.d b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.d
deleted file mode 100644
index 095d3ebe60e..00000000000
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.d
+++ /dev/null
@@ -1,3 +0,0 @@
-bin/kotlin_class_generator.o: src/kotlin_class_generator.cc \
- src/kotlin_class_generator.h src/kotlin_field_generator.h \
- src/kotlin_enum_generator.h
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.o b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.o
deleted file mode 100644
index ea513f2069d..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_class_generator.o and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.d b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.d
deleted file mode 100644
index 443a361d921..00000000000
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.d
+++ /dev/null
@@ -1,2 +0,0 @@
-bin/kotlin_enum_generator.o: src/kotlin_enum_generator.cc \
- src/kotlin_enum_generator.h
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.o b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.o
deleted file mode 100644
index acd6c6424c8..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_enum_generator.o and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.d b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.d
deleted file mode 100644
index 7e7089bbf82..00000000000
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.d
+++ /dev/null
@@ -1,2 +0,0 @@
-bin/kotlin_field_generator.o: src/kotlin_field_generator.cc \
- src/kotlin_field_generator.h
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.o b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.o
deleted file mode 100644
index a5945fe0345..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_field_generator.o and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.d b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.d
deleted file mode 100644
index 04d6f449aab..00000000000
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.d
+++ /dev/null
@@ -1,3 +0,0 @@
-bin/kotlin_file_generator.o: src/kotlin_file_generator.cc \
- src/kotlin_file_generator.h src/kotlin_class_generator.h \
- src/kotlin_field_generator.h src/kotlin_enum_generator.h
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.o b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.o
deleted file mode 100644
index a097a89d3ce..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/kotlin_file_generator.o and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.d b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.d
deleted file mode 100644
index ab59dd96054..00000000000
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.d
+++ /dev/null
@@ -1,3 +0,0 @@
-bin/main.o: src/main.cc src/kotlin_file_generator.h \
- src/kotlin_class_generator.h src/kotlin_field_generator.h \
- src/kotlin_enum_generator.h
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.o b/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.o
deleted file mode 100644
index 4fc05d90668..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/bin/main.o and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc
deleted file mode 100755
index 33dfa788ef6..00000000000
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc and /dev/null differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.cc
index 28838690de2..376c7aa5eec 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.cc
@@ -22,7 +22,7 @@ void ClassGenerator::generateCode(io::Printer *printer, bool isBuilder) const {
     * Also note that fields should be declared before init section.
     */
     for (FieldGenerator *gen: properties) {
-        gen->generateCode(printer, isBuilder);
+        gen->generateCode(printer, isBuilder, simpleName);
         printer->Print("\n");
     }
 
@@ -61,9 +61,6 @@ void ClassGenerator::generateCode(io::Printer *printer, bool isBuilder) const {
     if (isBuilder) {
         printer->Print("\n");
         generateBuildMethod(printer);
-
-        printer->Print("\n");
-        generateSetters(printer);
     }
 
     printer->Outdent();
@@ -72,7 +69,7 @@ void ClassGenerator::generateCode(io::Printer *printer, bool isBuilder) const {
 
 ClassGenerator::ClassGenerator(Descriptor const *descriptor)
     : descriptor(descriptor) {
-    simpleName = descriptor->name();    // TODO: think about more careful class naming
+    simpleName = descriptor->name();
 
     int field_count = descriptor->field_count();
     for (int i = 0; i < field_count; ++i) {
@@ -143,7 +140,6 @@ void ClassGenerator::generateSerializers(io::Printer * printer, bool isRead) con
                            "\n");
     printer->Indent();
 
-    //TODO: write message tag and size
     printer->Print(vars, "$maybeReturn$$funName$NoTag($arg$)\n");
 
     printer->Outdent();
@@ -234,14 +230,6 @@ void ClassGenerator::generateInitSection(io::Printer * printer) const {
     printer->Print("}\n");
 }
 
-void ClassGenerator::generateSetters(io::Printer *printer) const {
-    for (int i = 0; i < properties.size(); ++i) {
-        properties[i]->generateSetter(printer, "Builder" + simpleName);
-        printer->Print("\n");
-    }
-}
-
-
 const string ClassModifier::getName() const {
     string result = "";
     switch (type) {
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.h b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.h
index 6b9da71742f..27eeee7409c 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.h
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_class_generator.h
@@ -47,7 +47,6 @@ private:
     void generateBuilder (io::Printer * printer) const;
     void generateBuildMethod (io::Printer * printer) const;
     void generateInitSection (io::Printer * printer) const;
-    void generateSetters (io::Printer * printer) const;
     /**
      * Flag isBuilder used for reducing code repeating, as code for class itself
      * and for its inner builder are structurally very alike and can be generated
@@ -67,7 +66,7 @@ private:
 };
 
 } // namespace kotlin
-} // namspace compiler
+} // namespace compiler
 } // namespace protobuf
 } // namespace google
 #endif //SRC_KOTLIN_CLASS_GENERATOR_H
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.cc
index 1f976e31025..8d5bd9ad3b1 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.cc
@@ -114,6 +114,6 @@ EnumGenerator::EnumGenerator(EnumDescriptor const *descriptor) {
 }
 
 } // namespace kotlin
-} // namspace compiler
+} // namespace compiler
 } // namespace protobuf
 } // namespace google
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.h b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.h
index 3265777a488..5e9c9f1b9b0 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.h
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_enum_generator.h
@@ -36,7 +36,7 @@ private:
 };
 
 } // namespace kotlin
-} // namspace compiler
+} // namespace compiler
 } // namespace protobuf
 } // namespace google
 
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
index dcd9b714c44..7f7f13d78f2 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
@@ -6,6 +6,7 @@
 #include <vector>
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.h>
+#include "kotlin_name_resolver.h"
 #include <iostream>
 
 namespace google {
@@ -28,12 +29,19 @@ string FieldGenerator::protobufToKotlinField() const {
             postamble = "?";
             break;
         case FieldDescriptor::LABEL_REPEATED:
+        #ifndef KOTLIN_GENERATED_CODE_LANGUAGE_LEVEL_LOW
+            preamble = "MutableList <";
+            postamble = "> ";
+            break;
+        #else
             preamble  = "Array <";
             postamble = "> ";
             break;
+        #endif
     }
     return preamble + protobufToKotlinType() + postamble;
 }
+
 /**
  * Simply maps protobuf field type to corresponding Kotlin.
  */
@@ -43,7 +51,7 @@ string FieldGenerator::protobufToKotlinType() const {
         case FieldDescriptor::TYPE_BOOL:
             return "Boolean";
         case FieldDescriptor::TYPE_BYTES:
-            return "";  // TODO: support bytes type
+            return "ByteArray";
         case FieldDescriptor::TYPE_DOUBLE:
             return "Double";
         case FieldDescriptor::TYPE_ENUM:
@@ -56,8 +64,6 @@ string FieldGenerator::protobufToKotlinType() const {
             return "Long";
         case FieldDescriptor::TYPE_FLOAT:
             return "Float";
-        case FieldDescriptor::TYPE_GROUP:
-            return "";     // @deprecated //TODO: make proper error handling there
         case FieldDescriptor::TYPE_INT32:
             return "Int";
         case FieldDescriptor::TYPE_INT64:
@@ -82,25 +88,73 @@ string FieldGenerator::protobufToKotlinType() const {
 }
 
 string FieldGenerator::getInitValue() const {
-    if (descriptor->is_optional()) {
-        return "null";
-    }
     if (descriptor->is_repeated())
+    #ifndef KOTLIN_GENERATED_CODE_LANGUAGE_LEVEL_LOW
+        return "mutableListOf()";
+    #else
         return "arrayOf()";
-    return fullType + "()";
+    #endif
+
+    FieldDescriptor::Type type = descriptor->type();
+    switch(type) {
+        case FieldDescriptor::TYPE_BOOL:
+            return "false";
+        case FieldDescriptor::TYPE_BYTES:
+            return "ByteArray(0)";
+        case FieldDescriptor::TYPE_DOUBLE:
+            return "0.0";
+        case FieldDescriptor::TYPE_ENUM: {
+            string enumType = descriptor->enum_type()->name();
+            return enumType + ".fromIntTo" + enumType + "(0)";   // produce enum from 0, as demanded by Google
+        }
+        case FieldDescriptor::TYPE_FIXED32:
+            return "0";
+        case FieldDescriptor::TYPE_FIXED64:
+            return "0L";
+        case FieldDescriptor::TYPE_FLOAT:
+            return "0f";
+        case FieldDescriptor::TYPE_INT32:
+            return "0";
+        case FieldDescriptor::TYPE_INT64:
+            return "0L";
+        case FieldDescriptor::TYPE_MESSAGE:
+            return string(descriptor->message_type()->name()) + "()";
+        case FieldDescriptor::TYPE_SFIXED32:
+            return "0";
+        case FieldDescriptor::TYPE_SFIXED64:
+            return "0L";
+        case FieldDescriptor::TYPE_SINT32:
+            return "0";
+        case FieldDescriptor::TYPE_SINT64:
+            return "0L";
+        case FieldDescriptor::TYPE_STRING:
+            return "\"\"";
+        case FieldDescriptor::TYPE_UINT32:
+            return "0";            // see notes for TYPE_FIXED32
+        case FieldDescriptor::TYPE_UINT64:
+            return "0L";           // see notes for TYPE_FIXED64
+    }
 }
 
-void FieldGenerator::generateCode(io::Printer *printer, bool isBuilder) const {
+void FieldGenerator::generateCode(io::Printer *printer, bool isBuilder, string className) const {
     map<string, string> vars;
     vars["name"] = simpleName;
     vars["field"] = protobufToKotlinField();
     printer->Print(vars, "var $name$ : $field$\n");
 
-    // make setter private for fair classes
-    if (!isBuilder) {
-        printer->Indent();
-        printer->Print("private set\n");
-        printer->Outdent();
+    // make setter private
+    printer->Indent();
+    printer->Print("private set\n");
+    printer->Outdent();
+
+    // generate setter for builder
+    if (isBuilder) {
+        generateSetter(printer, /* builderName = */ "Builder" + className);
+    }
+
+    // generate additional methods for repeated fields
+    if (modifier == FieldDescriptor::LABEL_REPEATED) {
+        generateRepeatedMethods(printer, isBuilder, /* builderName = */ "Builder" + className);
     }
 }
 
@@ -137,7 +191,7 @@ void FieldGenerator::generateSerializationCode(io::Printer *printer, bool isRead
             //TODO: dirty stub here! Normally, reading from input should be delegated to Parsers, with proper error handling and etc.
             //Currently tag is ignored, and work of the library relies heavily on the field order guarantees.
             //Thus, backward-compability and extensions are not supported.
-            printer->Print(vars, "val tag = input.readTag()\n");
+            printer->Print(vars, "val tag = input.readTag($fieldNumber$, WireType.LENGTH_DELIMITED)\n");
             printer->Print(vars, "val listSize = input.readInt32NoTag()\n");
             printer->Print(vars, "for (i in 1..listSize) {\n");
             printer->Indent();
@@ -146,8 +200,12 @@ void FieldGenerator::generateSerializationCode(io::Printer *printer, bool isRead
             printer->Print("}\n");
         }
         else {
+            // tag
+            printer->Print(vars, "output.writeTag($fieldNumber$, WireType.LENGTH_DELIMITED)\n");
+
             // length
-            printer->Print(vars, "$arg$.writeInt32NoTag($fieldName$.size)\n");
+            printer->Print(vars, "output.writeInt32NoTag($fieldName$.size)\n");
+            printer->Print(vars, "output.writeInt32NoTag($fieldName$.size)\n");
 
             // all elements
             printer->Print(vars, "for (item in $fieldName$) {\n");
@@ -201,11 +259,16 @@ void FieldGenerator::generateSerializationCode(io::Printer *printer, bool isRead
     if (descriptor->type() == FieldDescriptor::TYPE_MESSAGE) {
         vars["fieldName"] = noTag ? "item" : simpleName;
         vars["maybeNoTag"] = noTag ? "NoTag" : "";
+        vars["fieldNumber"] = std::to_string(descriptor->number());
         if (isRead) {
-            printer->Print(vars, "$fieldName$.readFrom$maybeNoTag$(input)\n");
+            printer->Print(vars,
+                           "val tag = input.readTag($fieldNumber$, WireType.LENGTH_DELIMITED)\n"
+                           "$fieldName$.readFrom$maybeNoTag$(input)\n");
         }
         else {
-            printer->Print(vars, "$fieldName$.writeTo$maybeNoTag$(output)\n");
+            printer->Print(vars,
+                           "output.writeTag($fieldNumber$, WireType.LENGTH_DELIMITED)\n"
+                           "$fieldName$.writeTo$maybeNoTag$(output)\n");
         }
         return;
     }
@@ -217,9 +280,6 @@ void FieldGenerator::generateSerializationCode(io::Printer *printer, bool isRead
     else {
         printer->Print(vars, "output.write$type$ ($fieldNumber$, $fieldName$)\n");
     }
-
-
-    // TODO: support tricky types like enums/messages/repeated fields/etc
 }
 
 string FieldGenerator::protobufTypeToKotlinFunctionSuffix(FieldDescriptor::Type type) const {
@@ -242,12 +302,10 @@ string FieldGenerator::protobufTypeToKotlinFunctionSuffix(FieldDescriptor::Type
             return "Bool";
         case FieldDescriptor::TYPE_STRING:
             return "String";
-        case FieldDescriptor::TYPE_GROUP:
-            return "";   // deprecated  // TODO: think about proper error handling here
         case FieldDescriptor::TYPE_MESSAGE:
-            return "Message";   // TODO: support messages
+            return "Message";
         case FieldDescriptor::TYPE_BYTES:
-            return "";  // TODO: support bytes
+            return "Bytes";
         case FieldDescriptor::TYPE_UINT32:
             return "UInt32";
         case FieldDescriptor::TYPE_ENUM:
@@ -265,25 +323,67 @@ string FieldGenerator::protobufTypeToKotlinFunctionSuffix(FieldDescriptor::Type
 
 void FieldGenerator::generateSetter(io::Printer *printer, string builderName) const {
     map <string, string> vars;
-    // TODO: refactor work with names into separate class
-    string camelCaseName = simpleName;
-    camelCaseName[0] = char(std::toupper(camelCaseName[0]));
-    vars["camelCaseName"] = camelCaseName;
-    vars["name"] = simpleName;
+    vars["camelCaseName"] = name_resolving::makeFirstLetterUpper(simpleName);
+    vars["fieldName"] = simpleName;
     vars["builderName"] = builderName;
     vars["type"] = fullType;
     printer->Print(vars,
                     "fun set$camelCaseName$(value: $type$): $builderName$ {\n");
     printer->Indent();
     printer->Print(vars,
-                    "$name$ = value\n"
+                    "$fieldName$ = value\n"
                     "return this\n");
     printer->Outdent();
     printer->Print("}\n");
 }
 
+void FieldGenerator::generateRepeatedMethods(io::Printer * printer, bool isBuilder, string builderName) const {
+    map <string, string> vars;
+    vars["elementType"] = underlyingType;
+    vars["arg"] = "value";
+    vars["fieldName"] = simpleName;
+    vars["builderName"] = builderName;
+
+    // generate indexed setter for builders
+    if (isBuilder) {
+        printer->Print(vars, "fun set$elementType$(index: Int, $arg$: $elementType$): $builderName$ {\n");
+        printer->Indent();
+        printer->Print(vars, "$fieldName$[index] = $arg$\n");
+        printer->Print(vars, "return this\n");
+        printer->Outdent();
+        printer->Print("}\n");
+    }
+
+    #ifndef KOTLIN_GENERATED_CODE_LANGUAGE_LEVEL_LOW
+    if (isBuilder) {
+        // generate single-add for builders
+        printer->Print(vars, "fun add$elementType$($arg$: $elementType$): $builderName$ {\n");
+        printer->Indent();
+        printer->Print(vars, "$fieldName$.add($arg$)\n"
+                             "return this\n");
+        printer->Outdent();
+        printer->Print(vars, "}\n");
+
+        // generate addAll for builders
+        printer->Print(vars, "fun addAll$elementType$($arg$: Iterable<$elementType$>): $builderName$ {\n");
+        printer->Indent();
+        printer->Print(vars, "for (item in $arg$) {\n");
+        printer->Indent();
+        printer->Print(vars, "$fieldName$.add(item)\n");
+
+        printer->Outdent();     // for-loop
+        printer->Print("}\n");
+
+        printer->Print("return this\n");
+
+        printer->Outdent();     // function body
+        printer->Print("}\n");
+    }
+    #endif
+}
+
 
 } // namespace kotlin
-} // namspace compiler
+} // namespace compiler
 } // namespace protobuf
 } // namespace google
\ No newline at end of file
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.h b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.h
index e11c0dccec8..3e61f4beea4 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.h
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.h
@@ -30,7 +30,8 @@ private:
     *          CodedInputStream.readSFixed32(fieldNumber: Int)
     */
     string protobufTypeToKotlinFunctionSuffix(FieldDescriptor::Type type) const;
-
+    void generateSetter(io::Printer * printer, string builderName) const;
+    void generateRepeatedMethods(io::Printer * printer, bool isBuilder, string builderName) const;
 public:
     FieldDescriptor::Label modifier;
     string simpleName;
@@ -45,15 +46,14 @@ public:
     string fullType;
 
     string initValue;
-    void generateCode(io::Printer * printer, bool isBuilder = false) const;
+    void generateCode(io::Printer * printer, bool isBuilder, string className) const;
     void generateSerializationCode(io::Printer * printer, bool isRead = false, bool noTag = false) const;
-    void generateSetter(io::Printer * printer, string builderName) const;
     FieldGenerator(FieldDescriptor const * descriptor);
 
 };
 
 } // namespace kotlin
-} // namspace compiler
+} // namespace compiler
 } // namespace protobuf
 } // namespace google
 
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_file_generator.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_file_generator.cc
index 5ff54c22c5d..ee36d46f73d 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_file_generator.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_file_generator.cc
@@ -10,6 +10,7 @@
 #endif
 #include "kotlin_file_generator.h"
 #include <iostream>
+#include "kotlin_name_resolver.h"
 
 namespace google {
 namespace protobuf {
@@ -26,14 +27,7 @@ void FileGenerator::generateCode(io::Printer *printer, std::vector<ClassGenerato
 bool FileGenerator::Generate(const FileDescriptor *file, const string &parameter, GeneratorContext *context,
                              string *error) const {
     std::vector<ClassGenerator *> classes;
-
-    //TODO: maybe wrap work with class names and stuff in separate class (like in Java implementation)
-    // Get output file name
-    string const proto_file_name = file->name();
-    size_t file_extension_index = proto_file_name.find(".proto");
-    string const file_name = proto_file_name.substr(0, file_extension_index) + ".kt";
-
-
+    string const file_name = name_resolving::getKotlinOutputByProtoName(file->name());
     google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(context->Open(file_name));
     io::Printer printer(output.get(), '$', /* annotation_collector = */ NULL);
 
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.cc
new file mode 100644
index 00000000000..d0ff147e446
--- /dev/null
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.cc
@@ -0,0 +1,36 @@
+//
+// Created by user on 7/14/16.
+//
+
+#include "kotlin_name_resolver.h"
+#include <string>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace kotlin {
+
+namespace name_resolving {
+
+using namespace std;
+
+string makeFirstLetterUpper(std::string s) {
+    s[0] = std::toupper(s[0]);
+    return s;
+}
+
+string getFileNameWithoutExtension(string fullName) {
+    size_t file_extension_index = fullName.find_last_of(".");
+    return fullName.substr(0, file_extension_index);
+}
+
+string getKotlinOutputByProtoName(string protoName) {
+    string justName = getFileNameWithoutExtension(protoName);
+    return justName + ".kt";
+}
+
+} // namespace name_resolving
+} // namespace kotlin
+} // namespace compiler
+} // namespace protobuf
+} // namespace google
\ No newline at end of file
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.h b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.h
new file mode 100644
index 00000000000..ddf0453598b
--- /dev/null
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_name_resolver.h
@@ -0,0 +1,29 @@
+//
+// Created by user on 7/14/16.
+//
+
+#ifndef GOOGLE_KOTLIN_NAME_RESOLVER_H
+#define GOOGLE_KOTLIN_NAME_RESOLVER_H
+
+#include <string>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace kotlin {
+namespace name_resolving {
+
+std::string makeFirstLetterUpper(std::string s);
+
+std::string getFileNameWithoutExtension(std::string fullName);
+
+std::string getKotlinOutputByProtoName(std::string protoName);
+
+} // namespace name_resolving
+} // namespace kotlin
+} // namespace compiler
+} // namespace protobuf
+} // namespace google
+
+
+#endif //GOOGLE_KOTLIN_NAME_RESOLVER_H
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/main.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/main.cc
index 04e3267731a..9e4c462ef47 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/main.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/main.cc
@@ -3,8 +3,6 @@
 #include <google/protobuf/compiler/python/python_generator.h>
 #include <google/protobuf/compiler/java/java_generator.h>
 #include <google/protobuf/compiler/javanano/javanano_generator.h>
-// TODO(teboring): Add it back when php implementation is ready
-// #include <google/protobuf/compiler/php/php_generator.h>
 #include <google/protobuf/compiler/ruby/ruby_generator.h>
 #include <google/protobuf/compiler/csharp/csharp_generator.h>
 #include <google/protobuf/compiler/objectivec/objectivec_generator.h>
@@ -12,6 +10,7 @@
 #include "kotlin_file_generator.h"
 #include <iostream>
 
+//#define KOTLIN_GENERATED_CODE_LANGUAGE_LEVEL_LOW
 int main(int argc, const char* const * argv) {
   google::protobuf::compiler::CommandLineInterface cli;
 
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.kt b/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.kt
index a35c9e9c4f6..8f90ec5b6f0 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.kt
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.kt
@@ -1,4 +1,4 @@
-class Person private constructor (name: kotlin.String? = null, id: Int? = null, email: kotlin.String? = null, phones: Array <PhoneNumber>  = arrayOf()) {
+class Person private constructor (name: kotlin.String? = "", id: Int? = 0, email: kotlin.String? = "", phones: MutableList <PhoneNumber>  = mutableListOf(), someBytes: ByteArray? = ByteArray(0)) {
   var name : kotlin.String?
     private set
 
@@ -8,7 +8,10 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
   var email : kotlin.String?
     private set
 
-  var phones : Array <PhoneNumber> 
+  var phones : MutableList <PhoneNumber> 
+    private set
+
+  var someBytes : ByteArray?
     private set
 
 
@@ -17,6 +20,7 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
     this.id = id
     this.email = email
     this.phones = phones
+    this.someBytes = someBytes
   }
   enum class PhoneType(val ord: Int) {
     MOBILE (0),
@@ -34,7 +38,7 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
       }
     }
   }
-  class PhoneNumber private constructor (number: kotlin.String? = null, type: PhoneType? = null) {
+  class PhoneNumber private constructor (number: kotlin.String? = "", type: PhoneType? = PhoneType.fromIntToPhoneType(0)) {
     var number : kotlin.String?
       private set
 
@@ -47,19 +51,29 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
       this.type = type
     }
 
-    fun writeTo (output: CodedOutputStream) {
+    fun writeTo (output: CodedOutputStream): Unit {
       writeToNoTag(output)
     }
 
-    fun writeToNoTag (output: CodedOutputStream) {
+    fun writeToNoTag (output: CodedOutputStream): Unit {
       output.writeString (1, number)
       output.writeEnum (2, type?.ord)
     }
 
-    class BuilderPhoneNumber constructor (number: kotlin.String? = null, type: PhoneType? = null) {
+    class BuilderPhoneNumber constructor (number: kotlin.String? = "", type: PhoneType? = PhoneType.fromIntToPhoneType(0)) {
       var number : kotlin.String?
+        private set
+      fun setNumber(value: kotlin.String?): BuilderPhoneNumber {
+        number = value
+        return this
+      }
 
       var type : PhoneType?
+        private set
+      fun setType(value: PhoneType?): BuilderPhoneNumber {
+        type = value
+        return this
+      }
 
 
       init {
@@ -67,29 +81,19 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
         this.type = type
       }
 
-      fun readFrom (input: CodedInputStream) {
-        readFromNoTag(input)
+      fun readFrom (input: CodedInputStream): BuilderPhoneNumber {
+        return readFromNoTag(input)
       }
 
-      fun readFromNoTag (input: CodedInputStream) {
+      fun readFromNoTag (input: CodedInputStream): BuilderPhoneNumber {
         number = input.readString(1)
         type = PhoneType.fromIntToPhoneType(input.readEnum(2))
-      }
+        return this
+}
 
       fun build(): PhoneNumber {
         return PhoneNumber(number, type)
       }
-
-      fun setNumber(value: kotlin.String?): BuilderPhoneNumber {
-        number = value
-        return this
-      }
-
-      fun setType(value: PhoneType?): BuilderPhoneNumber {
-        type = value
-        return this
-      }
-
     }
 
     fun mergeFrom (input: CodedInputStream) {
@@ -99,30 +103,75 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
   }
 
 
-  fun writeTo (output: CodedOutputStream) {
+  fun writeTo (output: CodedOutputStream): Unit {
     writeToNoTag(output)
   }
 
-  fun writeToNoTag (output: CodedOutputStream) {
+  fun writeToNoTag (output: CodedOutputStream): Unit {
     output.writeString (1, name)
     output.writeInt32 (2, id)
     output.writeString (3, email)
     if (phones.size > 0) {
+      output.writeTag(4, WireType.LENGTH_DELIMITED)
+      output.writeInt32NoTag(phones.size)
       output.writeInt32NoTag(phones.size)
       for (item in phones) {
+        output.writeTag(4, WireType.LENGTH_DELIMITED)
         item.writeToNoTag(output)
       }
     }
+    output.writeBytes (5, someBytes)
   }
 
-  class BuilderPerson constructor (name: kotlin.String? = null, id: Int? = null, email: kotlin.String? = null, phones: Array <PhoneNumber>  = arrayOf()) {
+  class BuilderPerson constructor (name: kotlin.String? = "", id: Int? = 0, email: kotlin.String? = "", phones: MutableList <PhoneNumber>  = mutableListOf(), someBytes: ByteArray? = ByteArray(0)) {
     var name : kotlin.String?
+      private set
+    fun setName(value: kotlin.String?): BuilderPerson {
+      name = value
+      return this
+    }
 
     var id : Int?
+      private set
+    fun setId(value: Int?): BuilderPerson {
+      id = value
+      return this
+    }
 
     var email : kotlin.String?
+      private set
+    fun setEmail(value: kotlin.String?): BuilderPerson {
+      email = value
+      return this
+    }
 
-    var phones : Array <PhoneNumber> 
+    var phones : MutableList <PhoneNumber> 
+      private set
+    fun setPhones(value: MutableList <PhoneNumber> ): BuilderPerson {
+      phones = value
+      return this
+    }
+    fun setPhoneNumber(index: Int, value: PhoneNumber): BuilderPerson {
+      phones[index] = value
+      return this
+    }
+    fun addPhoneNumber(value: PhoneNumber): BuilderPerson {
+      phones.add(value)
+      return this
+    }
+    fun addAllPhoneNumber(value: Iterable<PhoneNumber>): BuilderPerson {
+      for (item in value) {
+        phones.add(item)
+      }
+      return this
+    }
+
+    var someBytes : ByteArray?
+      private set
+    fun setSomeBytes(value: ByteArray?): BuilderPerson {
+      someBytes = value
+      return this
+    }
 
 
     init {
@@ -130,49 +179,31 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
       this.id = id
       this.email = email
       this.phones = phones
+      this.someBytes = someBytes
     }
 
-    fun readFrom (input: CodedInputStream) {
-      readFromNoTag(input)
+    fun readFrom (input: CodedInputStream): BuilderPerson {
+      return readFromNoTag(input)
     }
 
-    fun readFromNoTag (input: CodedInputStream) {
+    fun readFromNoTag (input: CodedInputStream): BuilderPerson {
       name = input.readString(1)
       id = input.readInt32(2)
       email = input.readString(3)
       if (phones.size > 0) {
-        val tag = input.readTag()
+        val tag = input.readTag(4, WireType.LENGTH_DELIMITED)
         val listSize = input.readInt32NoTag()
         for (i in 1..listSize) {
           phones[i - 1].mergeFrom(input)
         }
       }
-    }
+      someBytes = input.readBytes(5)
+      return this
+}
 
     fun build(): Person {
-      return Person(name, id, email, phones)
+      return Person(name, id, email, phones, someBytes)
     }
-
-    fun setName(value: kotlin.String?): BuilderPerson {
-      name = value
-      return this
-    }
-
-    fun setId(value: Int?): BuilderPerson {
-      id = value
-      return this
-    }
-
-    fun setEmail(value: kotlin.String?): BuilderPerson {
-      email = value
-      return this
-    }
-
-    fun setPhones(value: Array <PhoneNumber> ): BuilderPerson {
-      phones = value
-      return this
-    }
-
   }
 
   fun mergeFrom (input: CodedInputStream) {
@@ -180,18 +211,19 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
     id = input.readInt32(2)
     email = input.readString(3)
     if (phones.size > 0) {
-      val tag = input.readTag()
+      val tag = input.readTag(4, WireType.LENGTH_DELIMITED)
       val listSize = input.readInt32NoTag()
       for (i in 1..listSize) {
         phones[i - 1].mergeFrom(input)
       }
     }
+    someBytes = input.readBytes(5)
   }
 }
 
 
-class AddressBook private constructor (people: Array <Person>  = arrayOf()) {
-  var people : Array <Person> 
+class AddressBook private constructor (people: MutableList <Person>  = mutableListOf()) {
+  var people : MutableList <Person> 
     private set
 
 
@@ -199,55 +231,72 @@ class AddressBook private constructor (people: Array <Person>  = arrayOf()) {
     this.people = people
   }
 
-  fun writeTo (output: CodedOutputStream) {
+  fun writeTo (output: CodedOutputStream): Unit {
     writeToNoTag(output)
   }
 
-  fun writeToNoTag (output: CodedOutputStream) {
+  fun writeToNoTag (output: CodedOutputStream): Unit {
     if (people.size > 0) {
+      output.writeTag(1, WireType.LENGTH_DELIMITED)
+      output.writeInt32NoTag(people.size)
       output.writeInt32NoTag(people.size)
       for (item in people) {
+        output.writeTag(1, WireType.LENGTH_DELIMITED)
         item.writeToNoTag(output)
       }
     }
   }
 
-  class BuilderAddressBook constructor (people: Array <Person>  = arrayOf()) {
-    var people : Array <Person> 
+  class BuilderAddressBook constructor (people: MutableList <Person>  = mutableListOf()) {
+    var people : MutableList <Person> 
+      private set
+    fun setPeople(value: MutableList <Person> ): BuilderAddressBook {
+      people = value
+      return this
+    }
+    fun setPerson(index: Int, value: Person): BuilderAddressBook {
+      people[index] = value
+      return this
+    }
+    fun addPerson(value: Person): BuilderAddressBook {
+      people.add(value)
+      return this
+    }
+    fun addAllPerson(value: Iterable<Person>): BuilderAddressBook {
+      for (item in value) {
+        people.add(item)
+      }
+      return this
+    }
 
 
     init {
       this.people = people
     }
 
-    fun readFrom (input: CodedInputStream) {
-      readFromNoTag(input)
+    fun readFrom (input: CodedInputStream): BuilderAddressBook {
+      return readFromNoTag(input)
     }
 
-    fun readFromNoTag (input: CodedInputStream) {
+    fun readFromNoTag (input: CodedInputStream): BuilderAddressBook {
       if (people.size > 0) {
-        val tag = input.readTag()
+        val tag = input.readTag(1, WireType.LENGTH_DELIMITED)
         val listSize = input.readInt32NoTag()
         for (i in 1..listSize) {
           people[i - 1].mergeFrom(input)
         }
       }
-    }
+      return this
+}
 
     fun build(): AddressBook {
       return AddressBook(people)
     }
-
-    fun setPeople(value: Array <Person> ): BuilderAddressBook {
-      people = value
-      return this
-    }
-
   }
 
   fun mergeFrom (input: CodedInputStream) {
     if (people.size > 0) {
-      val tag = input.readTag()
+      val tag = input.readTag(1, WireType.LENGTH_DELIMITED)
       val listSize = input.readInt32NoTag()
       for (i in 1..listSize) {
         people[i - 1].mergeFrom(input)
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.proto b/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.proto
index 23cc2f97e76..35bb149cd54 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.proto
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/test/addressbook.proto
@@ -38,6 +38,8 @@ message Person {
   }
 
   repeated PhoneNumber phones = 4;
+
+  bytes someBytes = 5;
 }
 
 // Our address book file is just one of these.
diff --git a/proto/compiler/src/CodedInputStream.kt b/proto/compiler/src/CodedInputStream.kt
index 1168cd65d94..d60c3ddc290 100644
--- a/proto/compiler/src/CodedInputStream.kt
+++ b/proto/compiler/src/CodedInputStream.kt
@@ -11,7 +11,7 @@ import java.nio.ByteOrder
  *
  */
 
-// TODO: decide, if we want to optimize for performance (then we have to deal with spaghetti-code)
+// TODO: refactor correctness checks into readTag
 class CodedInputStream(input: java.io.InputStream) {
 
     val bufferedInput: java.io.BufferedInputStream
@@ -20,7 +20,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readInt32(expectedFieldNumber: Int): Int {
-        val tag = readTag()
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
         val actualWireType = WireFormat.getTagWireType(tag)
         checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.VARINT, actualWireType)
@@ -31,10 +31,7 @@ class CodedInputStream(input: java.io.InputStream) {
     // simply stored in the sign bit - similar to Java's protobuf implementation. Hence, all
     // methods reading unsigned ints simply redirect call to corresponding signed-reading method
     fun readUInt32(expectedFieldNumber: Int): Int {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.VARINT, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readUInt32NoTag()
     }
 
@@ -43,19 +40,13 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readInt64(expectedFieldNumber: Int): Long {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, actualWireType, WireType.VARINT)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readInt64NoTag()
     }
 
     // See note on unsigned integers implementations above
     fun readUInt64(expectedFieldNumber: Int): Long {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, actualWireType, WireType.VARINT)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readUInt64NoTag()
     }
 
@@ -64,10 +55,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readBool(expectedFieldNumber: Int): Boolean {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, actualWireType, WireType.VARINT)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readBoolNoTag()
     }
 
@@ -83,10 +71,7 @@ class CodedInputStream(input: java.io.InputStream) {
 
     // Reading enums is like reading one int32 number. Caller is responsible for converting this ordinal to enum-object
     fun readEnum(expectedFieldNumber: Int): Int {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.VARINT, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readEnumNoTag()
     }
 
@@ -95,10 +80,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readSInt32(expectedFieldNumber: Int): Int {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.VARINT, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readSInt32NoTag()
     }
 
@@ -107,18 +89,12 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readSInt64(expectedFieldNumber: Int): Long {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.VARINT, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.VARINT)
         return readZigZag64NoTag()
     }
 
     fun readFixed32(expectedFieldNumber: Int): Int {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_32, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_32)
         return readFixed32NoInt()
     }
 
@@ -127,10 +103,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readSFixed32(expectedFieldNumber: Int): Int {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_32, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_32)
         return readSFixed32NoTag()
     }
 
@@ -139,10 +112,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readFixed64(expectedFieldNumber: Int): Long {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_64, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_64)
         return readFixed64NoTag()
     }
 
@@ -151,10 +121,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readSFixed64(expectedFieldNumber: Int): Long {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_64, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_64)
         return readSFixed64NoTag()
     }
 
@@ -163,10 +130,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readDouble(expectedFieldNumber: Int): Double {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_64, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_64)
         return readDoubleNoTag()
     }
 
@@ -175,10 +139,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readFloat(expectedFieldNumber: Int): Float {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.FIX_32, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.FIX_32)
         return readFloatNoTag()
     }
 
@@ -187,10 +148,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     fun readString(expectedFieldNumber: Int): String {
-        val tag = readTag()
-        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
-        val actualWireType = WireFormat.getTagWireType(tag)
-        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.LENGTH_DELIMITED, actualWireType)
+        val tag = readTag(expectedFieldNumber, WireType.LENGTH_DELIMITED)
         return readStringNoTag()
     }
 
@@ -199,6 +157,17 @@ class CodedInputStream(input: java.io.InputStream) {
         val value = String(readRawBytes(length))
         return value
     }
+
+    fun readBytes(expectedFieldNumber: Int): ByteArray {
+        val tag = readTag(expectedFieldNumber, WireType.LENGTH_DELIMITED)
+        return readBytesNoTag()
+    }
+
+    fun readBytesNoTag(): ByteArray {
+        val length = readInt32NoTag()
+        return readRawBytes(length)
+    }
+
     /** ============ Utility methods ==================
      *  They are left non-private for cases when one wants to implement her/his own protocol format.
      *  Then she/he can re-use low-level methods for operating with raw values, that are not annotated with Protobuf tags.
@@ -254,7 +223,7 @@ class CodedInputStream(input: java.io.InputStream) {
     }
 
     // reads tag. Note that it returns 0 for the end of message!
-    fun readTag(): Int {
+    fun readTag(expectedFieldNumber: Int, expectedWireType: WireType): Int {
         if (isAtEnd()) {
             return 0        // we can safely return 0 as sign of end of message, because 0-tags are illegal
         }
@@ -262,6 +231,10 @@ class CodedInputStream(input: java.io.InputStream) {
         if (tag == 0) {     // if we somehow had read 0-tag, then message is corrupted
             throw InvalidProtocolBufferException("Invalid tag 0")
         }
+
+        val actualFieldNumber = WireFormat.getTagFieldNumber(tag)
+        val actualWireType = WireFormat.getTagWireType(tag)
+        checkFieldCorrectness(expectedFieldNumber, actualFieldNumber, WireType.LENGTH_DELIMITED, actualWireType)
         return tag
     }
 
diff --git a/proto/compiler/src/CodedOutputStream.kt b/proto/compiler/src/CodedOutputStream.kt
index d5e132bc344..ea1fc24f0d3 100644
--- a/proto/compiler/src/CodedOutputStream.kt
+++ b/proto/compiler/src/CodedOutputStream.kt
@@ -151,6 +151,22 @@ class CodedOutputStream(val output: java.io.OutputStream) {
         output.write(value.toByteArray())
     }
 
+    fun writeBytes(fieldNumber: Int, value: ByteArray?) {
+        value ?: return
+        writeTag(fieldNumber, WireType.LENGTH_DELIMITED)
+        writeBytesNoTag(value)
+    }
+
+    fun writeBytesNoTag(value: ByteArray) {
+        writeInt32NoTag(value.size)
+        output.write(value)
+    }
+
+    /** ============ Utility methods ==================
+     *  They are left non-private for cases when one wants to implement her/his own protocol format.
+     *  Then she/he can re-use low-level methods for operating with raw values, that are not annotated with Protobuf tags.
+     */
+
     fun writeLittleEndian(value: Int?) {
         value ?: return
         val bb = ByteBuffer.allocate(4)
diff --git a/proto/compiler/src/PersonMessage.kt b/proto/compiler/src/PersonMessage.kt
index e29e0fb689b..cde8860f6a1 100644
--- a/proto/compiler/src/PersonMessage.kt
+++ b/proto/compiler/src/PersonMessage.kt
@@ -1,6 +1,4 @@
-package Addressbook;
-
-class Person private constructor (name: kotlin.String? = null, id: Int? = null, email: kotlin.String? = null, phones: Array <PhoneNumber>  = arrayOf()) {
+class Person private constructor (name: kotlin.String? = "", id: Int? = 0, email: kotlin.String? = "", phones: MutableList <PhoneNumber>  = mutableListOf(), someBytes: ByteArray? = ByteArray(0)) {
     var name : kotlin.String?
         private set
 
@@ -10,7 +8,10 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
     var email : kotlin.String?
         private set
 
-    var phones : Array <PhoneNumber>
+    var phones : MutableList <PhoneNumber>
+        private set
+
+    var someBytes : ByteArray?
         private set
 
 
@@ -19,8 +20,8 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
         this.id = id
         this.email = email
         this.phones = phones
+        this.someBytes = someBytes
     }
-
     enum class PhoneType(val ord: Int) {
         MOBILE (0),
         HOME (1),
@@ -37,7 +38,7 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
             }
         }
     }
-    class PhoneNumber private constructor (number: kotlin.String? = null, type: PhoneType? = null) {
+    class PhoneNumber private constructor (number: kotlin.String? = "", type: PhoneType? = PhoneType.fromIntToPhoneType(0)) {
         var number : kotlin.String?
             private set
 
@@ -50,19 +51,29 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
             this.type = type
         }
 
-        fun writeTo (output: CodedOutputStream) {
+        fun writeTo (output: CodedOutputStream): Unit {
             writeToNoTag(output)
         }
 
-        fun writeToNoTag (output: CodedOutputStream) {
+        fun writeToNoTag (output: CodedOutputStream): Unit {
             output.writeString (1, number)
             output.writeEnum (2, type?.ord)
         }
 
-        class BuilderPhoneNumber constructor (number: kotlin.String? = null, type: PhoneType? = null) {
+        class BuilderPhoneNumber constructor (number: kotlin.String? = "", type: PhoneType? = PhoneType.fromIntToPhoneType(0)) {
             var number : kotlin.String?
+                private set
+            fun setNumber(value: kotlin.String?): BuilderPhoneNumber {
+                number = value
+                return this
+            }
 
             var type : PhoneType?
+                private set
+            fun setType(value: PhoneType?): BuilderPhoneNumber {
+                type = value
+                return this
+            }
 
 
             init {
@@ -70,13 +81,14 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
                 this.type = type
             }
 
-            fun readFrom (input: CodedInputStream) {
-                readFromNoTag(input)
+            fun readFrom (input: CodedInputStream): BuilderPhoneNumber {
+                return readFromNoTag(input)
             }
 
-            fun readFromNoTag (input: CodedInputStream) {
+            fun readFromNoTag (input: CodedInputStream): BuilderPhoneNumber {
                 number = input.readString(1)
                 type = PhoneType.fromIntToPhoneType(input.readEnum(2))
+                return this
             }
 
             fun build(): PhoneNumber {
@@ -91,30 +103,75 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
     }
 
 
-    fun writeTo (output: CodedOutputStream) {
+    fun writeTo (output: CodedOutputStream): Unit {
         writeToNoTag(output)
     }
 
-    fun writeToNoTag (output: CodedOutputStream) {
+    fun writeToNoTag (output: CodedOutputStream): Unit {
         output.writeString (1, name)
         output.writeInt32 (2, id)
         output.writeString (3, email)
         if (phones.size > 0) {
+            output.writeTag(4, WireType.LENGTH_DELIMITED)
+            output.writeInt32NoTag(phones.size)
             output.writeInt32NoTag(phones.size)
             for (item in phones) {
+                output.writeTag(4, WireType.LENGTH_DELIMITED)
                 item.writeToNoTag(output)
             }
         }
+        output.writeBytes (5, someBytes)
     }
 
-    class BuilderPerson constructor (name: kotlin.String? = null, id: Int? = null, email: kotlin.String? = null, phones: Array <PhoneNumber>  = arrayOf()) {
+    class BuilderPerson constructor (name: kotlin.String? = "", id: Int? = 0, email: kotlin.String? = "", phones: MutableList <PhoneNumber>  = mutableListOf(), someBytes: ByteArray? = ByteArray(0)) {
         var name : kotlin.String?
+            private set
+        fun setName(value: kotlin.String?): BuilderPerson {
+            name = value
+            return this
+        }
 
         var id : Int?
+            private set
+        fun setId(value: Int?): BuilderPerson {
+            id = value
+            return this
+        }
 
         var email : kotlin.String?
+            private set
+        fun setEmail(value: kotlin.String?): BuilderPerson {
+            email = value
+            return this
+        }
 
-        var phones : Array <PhoneNumber>
+        var phones : MutableList <PhoneNumber>
+            private set
+        fun setPhones(value: MutableList <PhoneNumber> ): BuilderPerson {
+            phones = value
+            return this
+        }
+        fun setPhoneNumber(index: Int, value: PhoneNumber): BuilderPerson {
+            phones[index] = value
+            return this
+        }
+        fun addPhoneNumber(value: PhoneNumber): BuilderPerson {
+            phones.add(value)
+            return this
+        }
+        fun addAllPhoneNumber(value: Iterable<PhoneNumber>): BuilderPerson {
+            for (item in value) {
+                phones.add(item)
+            }
+            return this
+        }
+
+        var someBytes : ByteArray?
+            private set
+        fun setSomeBytes(value: ByteArray?): BuilderPerson {
+            someBytes = value
+            return this
+        }
 
 
         init {
@@ -122,27 +179,30 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
             this.id = id
             this.email = email
             this.phones = phones
+            this.someBytes = someBytes
         }
 
-        fun readFrom (input: CodedInputStream) {
-            readFromNoTag(input)
+        fun readFrom (input: CodedInputStream): BuilderPerson {
+            return readFromNoTag(input)
         }
 
-        fun readFromNoTag (input: CodedInputStream) {
+        fun readFromNoTag (input: CodedInputStream): BuilderPerson {
             name = input.readString(1)
             id = input.readInt32(2)
             email = input.readString(3)
             if (phones.size > 0) {
-                val tag = input.readTag()
+                val tag = input.readTag(4, WireType.LENGTH_DELIMITED)
                 val listSize = input.readInt32NoTag()
                 for (i in 1..listSize) {
                     phones[i - 1].mergeFrom(input)
                 }
             }
+            someBytes = input.readBytes(5)
+            return this
         }
 
         fun build(): Person {
-            return Person(name, id, email, phones)
+            return Person(name, id, email, phones, someBytes)
         }
     }
 
@@ -151,18 +211,19 @@ class Person private constructor (name: kotlin.String? = null, id: Int? = null,
         id = input.readInt32(2)
         email = input.readString(3)
         if (phones.size > 0) {
-            val tag = input.readTag()
+            val tag = input.readTag(4, WireType.LENGTH_DELIMITED)
             val listSize = input.readInt32NoTag()
             for (i in 1..listSize) {
                 phones[i - 1].mergeFrom(input)
             }
         }
+        someBytes = input.readBytes(5)
     }
 }
 
 
-class AddressBook private constructor (people: Array <Person>  = arrayOf()) {
-    var people : Array <Person>
+class AddressBook private constructor (people: MutableList <Person>  = mutableListOf()) {
+    var people : MutableList <Person>
         private set
 
 
@@ -170,39 +231,62 @@ class AddressBook private constructor (people: Array <Person>  = arrayOf()) {
         this.people = people
     }
 
-    fun writeTo (output: CodedOutputStream) {
+    fun writeTo (output: CodedOutputStream): Unit {
         writeToNoTag(output)
     }
 
-    fun writeToNoTag (output: CodedOutputStream) {
+    fun writeToNoTag (output: CodedOutputStream): Unit {
         if (people.size > 0) {
+            output.writeTag(1, WireType.LENGTH_DELIMITED)
+            output.writeInt32NoTag(people.size)
             output.writeInt32NoTag(people.size)
             for (item in people) {
+                output.writeTag(1, WireType.LENGTH_DELIMITED)
                 item.writeToNoTag(output)
             }
         }
     }
 
-    class BuilderAddressBook constructor (people: Array <Person>  = arrayOf()) {
-        var people : Array <Person>
+    class BuilderAddressBook constructor (people: MutableList <Person>  = mutableListOf()) {
+        var people : MutableList <Person>
+            private set
+        fun setPeople(value: MutableList <Person> ): BuilderAddressBook {
+            people = value
+            return this
+        }
+        fun setPerson(index: Int, value: Person): BuilderAddressBook {
+            people[index] = value
+            return this
+        }
+        fun addPerson(value: Person): BuilderAddressBook {
+            people.add(value)
+            return this
+        }
+        fun addAllPerson(value: Iterable<Person>): BuilderAddressBook {
+            for (item in value) {
+                people.add(item)
+            }
+            return this
+        }
 
 
         init {
             this.people = people
         }
 
-        fun readFrom (input: CodedInputStream) {
-            readFromNoTag(input)
+        fun readFrom (input: CodedInputStream): BuilderAddressBook {
+            return readFromNoTag(input)
         }
 
-        fun readFromNoTag (input: CodedInputStream) {
+        fun readFromNoTag (input: CodedInputStream): BuilderAddressBook {
             if (people.size > 0) {
-                val tag = input.readTag()
+                val tag = input.readTag(1, WireType.LENGTH_DELIMITED)
                 val listSize = input.readInt32NoTag()
                 for (i in 1..listSize) {
                     people[i - 1].mergeFrom(input)
                 }
             }
+            return this
         }
 
         fun build(): AddressBook {
@@ -212,7 +296,7 @@ class AddressBook private constructor (people: Array <Person>  = arrayOf()) {
 
     fun mergeFrom (input: CodedInputStream) {
         if (people.size > 0) {
-            val tag = input.readTag()
+            val tag = input.readTag(1, WireType.LENGTH_DELIMITED)
             val listSize = input.readInt32NoTag()
             for (i in 1..listSize) {
                 people[i - 1].mergeFrom(input)
diff --git a/proto/compiler/src/TestMessages.kt b/proto/compiler/src/TestMessages.kt
index b37fa3e48f5..c2d25d0f9af 100644
--- a/proto/compiler/src/TestMessages.kt
+++ b/proto/compiler/src/TestMessages.kt
@@ -5,18 +5,40 @@ import java.io.ByteArrayOutputStream
  * Created by user on 7/8/16.
  */
 
-import PersonMessage
-
 fun testMessageSerialization() {
+    // Messages work only with CodedStream classes, provided by ProtoKot-runtime library.
+    // One can create CodedStream passing any instance of corresponding Stream from Java's library.
     val s = ByteArrayOutputStream()
     val outs = CodedOutputStream(s)
-    val msg =
+
+    // All messages are immutable. Use Builders for creating new messages
+    val msg = Person.BuilderPerson()
+            .setEmail("wtf@dasda.com")  // all setters return this builder, so you could chain modifiers in LINQ-style
+            .setId(42)
+            .setName("John Doe")
+            .setPhones(arrayOf(         // repeated fields stored as Array<>, so use arrayOf() for creating repeated fields
+                    Person.PhoneNumber.BuilderPhoneNumber()
+                            .setNumber("342143-23423-42")
+                            .setType(Person.PhoneType.HOME)
+                            .build()
+            ))
+            .build()    // don't forget to call build() to produce message
     msg.writeTo(outs)
 
-    val ins = CodedInputStream(ByteArrayInputStream(s.toByteArray()))
-    val readMsg = Person("", 0, "", arrayOf())
+    // Now let's use output stream as input to read our message from it!
+    var ins = CodedInputStream(ByteArrayInputStream(s.toByteArray()))
+
+    // Create default instance of message
+    var readMsg = Person.BuilderPerson().build()
+    // Read in that message data from input stream.
     readMsg.mergeFrom(ins)
 
+    // Note, that currently mergeFrom is the only way to mutate instance of message.
+    // Don't rely on it, probably mergeFrom will be refactored lately to guarantee full immutability of mesages.
+
+    // Better way to read a message:
+    ins = CodedInputStream(ByteArrayInputStream(s.toByteArray()))
+    readMsg = Person.BuilderPerson().readFrom(ins).build()
     assert(msg == readMsg)
 }