diff --git a/include/ArduinoJson/Internals/CompactJsonWriter.hpp b/include/ArduinoJson/Internals/CompactJsonWriter.hpp
index dcc1e7e7..bba6f567 100644
--- a/include/ArduinoJson/Internals/CompactJsonWriter.hpp
+++ b/include/ArduinoJson/Internals/CompactJsonWriter.hpp
@@ -15,14 +15,14 @@ class CompactJsonWriter : public JsonWriter {
  public:
   explicit CompactJsonWriter(Print *sink) : JsonWriter(sink) {}
 
-  virtual void beginArray() { _length += _sink->write('['); }
-  virtual void endArray() { _length += _sink->write(']'); }
+  void beginArray() { _length += _sink->write('['); }
+  void endArray() { _length += _sink->write(']'); }
 
-  virtual void beginObject() { _length += _sink->write('{'); }
-  virtual void endObject() { _length += _sink->write('}'); }
+  void beginObject() { _length += _sink->write('{'); }
+  void endObject() { _length += _sink->write('}'); }
 
-  virtual void writeColon() { _length += _sink->write(':'); }
-  virtual void writeComma() { _length += _sink->write(','); }
+  void writeColon() { _length += _sink->write(':'); }
+  void writeComma() { _length += _sink->write(','); }
 };
 }
 }
diff --git a/include/ArduinoJson/Internals/JsonWriter.hpp b/include/ArduinoJson/Internals/JsonWriter.hpp
index 56002d2a..2c6b7d37 100644
--- a/include/ArduinoJson/Internals/JsonWriter.hpp
+++ b/include/ArduinoJson/Internals/JsonWriter.hpp
@@ -17,12 +17,8 @@ class JsonWriter {
 
   size_t bytesWritten() { return _length; }
 
-  virtual void beginArray() = 0;
-  virtual void endArray() = 0;
   void writeEmptyArray() { _length += _sink->print("[]"); }
 
-  virtual void beginObject() = 0;
-  virtual void endObject() = 0;
   void writeEmptyObject() { _length += _sink->print("{}"); }
 
   void writeString(const char *value);
@@ -30,9 +26,6 @@ class JsonWriter {
   void writeBoolean(bool value);
   void writeDouble(double value, int decimals);
 
-  virtual void writeColon() = 0;
-  virtual void writeComma() = 0;
-
  protected:
   Print *_sink;
   size_t _length;
diff --git a/include/ArduinoJson/Internals/PrettyJsonWriter.hpp b/include/ArduinoJson/Internals/PrettyJsonWriter.hpp
index ec2ea27a..43d62b2b 100644
--- a/include/ArduinoJson/Internals/PrettyJsonWriter.hpp
+++ b/include/ArduinoJson/Internals/PrettyJsonWriter.hpp
@@ -17,29 +17,29 @@ class PrettyJsonWriter : public JsonWriter {
   explicit PrettyJsonWriter(IndentedPrint *sink)
       : JsonWriter(sink), _indenter(sink) {}
 
-  virtual void beginArray() {
+  void beginArray() {
     _length += _sink->write('[');
     indent();
   }
 
-  virtual void endArray() {
+  void endArray() {
     unindent();
     _length += _sink->write(']');
   }
 
-  virtual void writeColon() { _length += _sink->print(": "); }
+  void writeColon() { _length += _sink->print(": "); }
 
-  virtual void writeComma() {
+  void writeComma() {
     _length += _sink->write(',');
     _length += _indenter->println();
   }
 
-  virtual void beginObject() {
+  void beginObject() {
     _length += _sink->write('{');
     indent();
   }
 
-  virtual void endObject() {
+  void endObject() {
     unindent();
     _length += _sink->write('}');
   }
diff --git a/include/ArduinoJson/JsonPrintable.hpp b/include/ArduinoJson/JsonPrintable.hpp
index 817670bb..f1709f67 100644
--- a/include/ArduinoJson/JsonPrintable.hpp
+++ b/include/ArduinoJson/JsonPrintable.hpp
@@ -9,18 +9,16 @@
 #include "Arduino/Printable.hpp"
 #include "Internals/StringBuilder.hpp"
 #include "Internals/IndentedPrint.hpp"
+#include "Internals/CompactJsonWriter.hpp"
+#include "Internals/PrettyJsonWriter.hpp"
 
 namespace ArduinoJson {
 
-namespace Internals {
-class IndentedPrint;
-}
-
 template <typename T>
 class JsonPrintable : public Printable {
  public:
   size_t printTo(Print &print) const {
-    CompactJsonWriter writer(&p);
+    Internals::CompactJsonWriter writer(&print);
     downcast().writeTo(writer);
     return writer.bytesWritten();
   }
@@ -30,7 +28,7 @@ class JsonPrintable : public Printable {
   }
 
   size_t prettyPrintTo(Internals::IndentedPrint &print) const {
-    PrettyJsonWriter writer(&p);
+    Internals::PrettyJsonWriter writer(&print);
     downcast().writeTo(writer);
     return writer.bytesWritten();
   }
@@ -45,6 +43,6 @@ class JsonPrintable : public Printable {
   }
 
  private:
-  const T &downcast() { return *static_cast<const T *>(this); }
+  const T &downcast() const { return *static_cast<const T *>(this); }
 };
 }
diff --git a/src/JsonValue.cpp b/src/JsonValue.cpp
index c0e8a890..cbfd2d03 100644
--- a/src/JsonValue.cpp
+++ b/src/JsonValue.cpp
@@ -7,7 +7,8 @@
 #include "ArduinoJson/JsonValue.hpp"
 #include "ArduinoJson/JsonArray.hpp"
 #include "ArduinoJson/JsonObject.hpp"
-#include "ArduinoJson/Internals/JsonWriter.hpp"
+#include "ArduinoJson/Internals/CompactJsonWriter.hpp"
+#include "ArduinoJson/Internals/PrettyJsonWriter.hpp"
 
 using namespace ArduinoJson;
 using namespace ArduinoJson::Internals;
@@ -74,7 +75,8 @@ void JsonValue::set(JsonObject &object) {
   _content.asObject = &object;
 }
 
-void JsonValue::writeTo(JsonWriter &writer) const {
+template <typename T>
+void JsonValue::writeTo(T &writer) const {
   switch (_type) {
     case JSON_ARRAY:
       _content.asArray->writeTo(writer);
@@ -101,3 +103,6 @@ void JsonValue::writeTo(JsonWriter &writer) const {
       break;
   }
 }
+
+template void JsonValue::writeTo<CompactJsonWriter>(CompactJsonWriter &) const;
+template void JsonValue::writeTo<PrettyJsonWriter>(PrettyJsonWriter &) const;
diff --git a/test/Issue10.cpp b/test/Issue10.cpp
index 0dc7da78..b1a0c481 100644
--- a/test/Issue10.cpp
+++ b/test/Issue10.cpp
@@ -30,7 +30,8 @@ class Issue10 : public testing::Test {
     persons[1] = employee;
   }
 
-  void checkJsonString(JsonPrintable &p) {
+  template <typename T>
+  void checkJsonString(const T &p) {
     char buffer[256];
     p.printTo(buffer, sizeof(buffer));
 
@@ -38,7 +39,7 @@ class Issue10 : public testing::Test {
                  buffer);
   }
 
-  StaticJsonBuffer<JSON_ARRAY_SIZE(2)+2*JSON_OBJECT_SIZE(2)> json;
+  StaticJsonBuffer<JSON_ARRAY_SIZE(2) + 2 * JSON_OBJECT_SIZE(2)> json;
   Person persons[2];
 };
 
@@ -51,7 +52,7 @@ TEST_F(Issue10, PopulateArrayByAddingAnObject) {
     object["id"] = persons[i].id;
     object["name"] = persons[i].name;
 
-    array.add(object); 
+    array.add(object);
   }
 
   checkJsonString(array);