diff --git a/src/converter/immutable_converter.cc b/src/converter/immutable_converter.cc
index 7e39b59..ba2ff38 100644
--- a/src/converter/immutable_converter.cc
+++ b/src/converter/immutable_converter.cc
@@ -50,6 +50,7 @@
 #include "converter/lattice.h"
 #include "converter/nbest_generator.h"
 #include "converter/node.h"
+#include "converter/node_allocator.h"
 #include "converter/node_list_builder.h"
 #include "converter/segmenter_interface.h"
 #include "converter/segments.h"
@@ -80,7 +81,7 @@
   KeyCorrectedNodeListBuilder(size_t pos,
                               StringPiece original_lookup_key,
                               const KeyCorrector *key_corrector,
-                              NodeAllocatorInterface *allocator)
+                              NodeAllocator *allocator)
       : BaseNodeListBuilder(allocator, allocator->max_nodes_size()),
         pos_(pos),
         original_lookup_key_(original_lookup_key),
@@ -739,7 +740,7 @@
 
 class NodeListBuilderWithCacheEnabled : public NodeListBuilderForLookupPrefix {
  public:
-  NodeListBuilderWithCacheEnabled(NodeAllocatorInterface *allocator,
+  NodeListBuilderWithCacheEnabled(NodeAllocator *allocator,
                                   size_t min_key_length)
       : NodeListBuilderForLookupPrefix(allocator,
                                        allocator->max_nodes_size(),
@@ -1187,7 +1188,7 @@
 // Adds penalty for predictive nodes when building a node list.
 class NodeListBuilderForPredictiveNodes : public BaseNodeListBuilder {
  public:
-  NodeListBuilderForPredictiveNodes(NodeAllocatorInterface *allocator,
+  NodeListBuilderForPredictiveNodes(NodeAllocator *allocator,
                                     int limit, const POSMatcher *pos_matcher)
       : BaseNodeListBuilder(allocator, limit), pos_matcher_(pos_matcher) {}
 
diff --git a/src/converter/lattice.cc b/src/converter/lattice.cc
index 6e48454..add7f7c 100644
--- a/src/converter/lattice.cc
+++ b/src/converter/lattice.cc
@@ -149,7 +149,7 @@
 
 Lattice::~Lattice() {}
 
-NodeAllocatorInterface *Lattice::node_allocator() const {
+NodeAllocator *Lattice::node_allocator() const {
   return node_allocator_.get();
 }
 
diff --git a/src/converter/lattice.h b/src/converter/lattice.h
index a84d91c..31b5f5d 100644
--- a/src/converter/lattice.h
+++ b/src/converter/lattice.h
@@ -36,19 +36,17 @@
 #include "base/port.h"
 #include "base/scoped_ptr.h"
 #include "base/string_piece.h"
+#include "converter/node.h"
+#include "converter/node_allocator.h"
 
 namespace mozc {
 
-struct Node;
-class NodeAllocator;
-class NodeAllocatorInterface;
-
 class Lattice {
  public:
   Lattice();
   ~Lattice();
 
-  NodeAllocatorInterface *node_allocator() const;
+  NodeAllocator *node_allocator() const;
 
   // set key and initalizes lattice with key.
   void SetKey(StringPiece key);
diff --git a/src/converter/node.h b/src/converter/node.h
index c3221aa..b5640f5 100644
--- a/src/converter/node.h
+++ b/src/converter/node.h
@@ -234,25 +234,6 @@
   }
 };
 
-class NodeAllocatorInterface {
- public:
-  NodeAllocatorInterface() : max_nodes_size_(8192) {}
-  virtual ~NodeAllocatorInterface() {}
-
-  virtual Node *NewNode() = 0;
-
-  virtual size_t max_nodes_size() const {
-    return max_nodes_size_;
-  }
-
-  virtual void set_max_nodes_size(size_t max_nodes_size) {
-    max_nodes_size_ = max_nodes_size;
-  }
-
- private:
-  size_t max_nodes_size_;
-};
-
 }  // namespace mozc
 
 #endif  // MOZC_CONVERTER_NODE_H_
diff --git a/src/converter/node_allocator.h b/src/converter/node_allocator.h
index 7a69236..eaf3fd3 100644
--- a/src/converter/node_allocator.h
+++ b/src/converter/node_allocator.h
@@ -30,19 +30,20 @@
 #ifndef MOZC_CONVERTER_NODE_ALLOCATOR_H_
 #define MOZC_CONVERTER_NODE_ALLOCATOR_H_
 
-#include "base/port.h"
 #include "base/freelist.h"
 #include "base/logging.h"
+#include "base/port.h"
 #include "converter/node.h"
 
 namespace mozc {
 
-class NodeAllocator : public NodeAllocatorInterface {
+class NodeAllocator {
  public:
-  NodeAllocator() : node_freelist_(1024), node_count_(0) {}
-  virtual ~NodeAllocator() {}
+  NodeAllocator() : node_freelist_(1024), max_nodes_size_(8192),
+                    node_count_(0) {}
+  ~NodeAllocator() {}
 
-  virtual Node *NewNode() {
+  Node *NewNode() {
     Node *node = node_freelist_.Alloc();
     DCHECK(node);
     node->Init();
@@ -50,18 +51,27 @@
     return node;
   }
 
-  // Free all nodes allocateed by NewNode()
+  // Frees all nodes allocateed by NewNode().
   void Free() {
     node_freelist_.Free();
     node_count_ = 0;
   }
 
+  size_t max_nodes_size() const {
+    return max_nodes_size_;
+  }
+
+  void set_max_nodes_size(size_t max_nodes_size) {
+    max_nodes_size_ = max_nodes_size;
+  }
+
   size_t node_count() const {
     return node_count_;
   }
 
  private:
   FreeList<Node> node_freelist_;
+  size_t max_nodes_size_;
   size_t node_count_;
 
   DISALLOW_COPY_AND_ASSIGN(NodeAllocator);
diff --git a/src/converter/node_list_builder.h b/src/converter/node_list_builder.h
index 4c7a359..601adb9 100644
--- a/src/converter/node_list_builder.h
+++ b/src/converter/node_list_builder.h
@@ -30,8 +30,8 @@
 #ifndef MOZC_CONVERTER_NODE_LIST_BUILDER_H_
 #define MOZC_CONVERTER_NODE_LIST_BUILDER_H_
 
-#include "base/port.h"
 #include "base/logging.h"
+#include "base/port.h"
 #include "base/trie.h"
 #include "converter/node.h"
 #include "dictionary/dictionary_interface.h"
@@ -47,7 +47,7 @@
 // dictionary lookup.
 class BaseNodeListBuilder : public DictionaryInterface::Callback {
  public:
-  BaseNodeListBuilder(NodeAllocatorInterface *allocator, int limit)
+  BaseNodeListBuilder(NodeAllocator *allocator, int limit)
       : allocator_(allocator), limit_(limit), penalty_(0), result_(NULL) {
     DCHECK(allocator_) << "Allocator must not be NULL";
   }
@@ -71,7 +71,7 @@
   int limit() const { return limit_; }
   int penalty() const { return penalty_; }
   Node *result() const { return result_; }
-  NodeAllocatorInterface *allocator() { return allocator_; }
+  NodeAllocator *allocator() { return allocator_; }
 
   Node *NewNodeFromToken(const Token &token) {
     Node *new_node = allocator_->NewNode();
@@ -87,7 +87,7 @@
   }
 
  protected:
-  NodeAllocatorInterface *allocator_;
+  NodeAllocator *allocator_;
   int limit_;
   int penalty_;
   Node *result_;
@@ -100,7 +100,7 @@
 // This class is also defined inline.
 class NodeListBuilderForLookupPrefix : public BaseNodeListBuilder {
  public:
-  NodeListBuilderForLookupPrefix(NodeAllocatorInterface *allocator,
+  NodeListBuilderForLookupPrefix(NodeAllocator *allocator,
                                  int limit, size_t min_key_length)
       : BaseNodeListBuilder(allocator, limit),
         min_key_length_(min_key_length) {}
diff --git a/src/dictionary/dictionary_mock.h b/src/dictionary/dictionary_mock.h
index af30841..5899eae 100644
--- a/src/dictionary/dictionary_mock.h
+++ b/src/dictionary/dictionary_mock.h
@@ -63,9 +63,6 @@
 
 namespace mozc {
 
-// These structures are defined in converter
-class NodeAllocatorInterface;
-
 class DictionaryMock : public DictionaryInterface {
  public:
   DictionaryMock();
diff --git a/src/mozc_version_template.txt b/src/mozc_version_template.txt
index 573db73..30a183c 100644
--- a/src/mozc_version_template.txt
+++ b/src/mozc_version_template.txt
@@ -1,6 +1,6 @@
 MAJOR=2
 MINOR=16
-BUILD=2064
+BUILD=2065
 REVISION=102
 # NACL_DICTIONARY_VERSION is the target version of the system dictionary to be
 # downloaded by NaCl Mozc.