--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/JungleTree.java	Fri Mar 06 10:59:34 2015 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/JungleTree.java	Sun Mar 15 14:57:26 2015 +0900
@@ -14,7 +14,7 @@
 {
 	public JungleTreeEditor getTreeEditor();
 	public JungleTreeEditor getLocalTreeEditor();
-	public TreeNode getRootNode();
+    public TreeNode getRootNode();
   public long revision();
   public Either<Error, JungleTree> getOldTree(long revision);
   public TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> getIndex();

--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/DefaultTreeOperationLog.java	Fri Mar 06 10:59:34 2015 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/store/impl/logger/DefaultTreeOperationLog.java	Sun Mar 15 14:57:26 2015 +0900
@@ -3,7 +3,6 @@
 import java.util.Iterator;
 
 import com.google.common.collect.Iterables;
-
 import fj.data.List;
 
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.NodePath;

--- a/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/InterfaceTraverser.java	Fri Mar 06 10:59:34 2015 +0900
+++ b/src/main/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/traverser/InterfaceTraverser.java	Sun Mar 15 14:57:26 2015 +0900
@@ -4,6 +4,7 @@
 
 import fj.Ord;
 import fj.P2;
+import fj.data.List;
 import fj.data.Option;
 import fj.data.TreeMap;
 import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.NulIterator;
@@ -17,7 +18,7 @@
 public class InterfaceTraverser {
 
   TreeNode node;
-  TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> index;
+  TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> indexList;
   ParentIndex parentIndex;
   boolean parentUpdateFlag;
   IndexManager indexManager;
@@ -30,7 +31,7 @@
   public InterfaceTraverser(TreeNode root, TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> index,
       ParentIndex parentIndex, IndexManager indexManager, boolean useIndex) {
     this.node = root;
-    this.index = index;
+    this.indexList = index;
     this.indexManager = indexManager;
     this.parentIndex = parentIndex;
     if (parentIndex.isEmpty())
@@ -41,12 +42,12 @@
   }
 
   public TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> getIndex() {
-    return index;
+    return indexList;
   }
 
   public void commit() {
     parentUpdateFlag = false;
-    indexManager.commit(index, parentIndex);
+    indexManager.commit(indexList, parentIndex);
   }
 
   public ParentIndex getParentIndex() {
@@ -54,7 +55,7 @@
   }
 
   public void setIndex(TreeMap<String, TreeMap<String, TreeMap<TreeNode, TreeNode>>> index) {
-    this.index = index;
+    this.indexList = index;
   }
 
   public void createIndex() {
@@ -62,7 +63,7 @@
     IndexCreater creater = new IndexCreater(node);
     // long t2 = System.currentTimeMillis();
     // System.out.println("createIndex time = " + (t2 - t1));
-    index = creater.getIndex();
+    indexList = creater.getIndex();
     parentIndex = creater.getParentIndex();
   }
 
@@ -212,7 +213,7 @@
   public Iterator<TreeNode> find(final Query query, final String key, String searchValue) {
 
     Iterator<TreeNode> nodeIterator = get(key, searchValue);
-    if (nodeIterator.hasNext() && useIndex) {
+    if (nodeIterator != null && useIndex) {
       return nodeIterator;
     } else {
 
@@ -323,9 +324,9 @@
   
   public Iterator<TreeNode> get(String key, String value) {
 
-    Option<TreeMap<String, TreeMap<TreeNode, TreeNode>>> indexOp = index.get(key);
+    Option<TreeMap<String, TreeMap<TreeNode, TreeNode>>> indexOp = indexList.get(key);
     if (indexOp.isNone())
-      return new NulIterator<TreeNode>();
+      return null;
 
     TreeMap<String, TreeMap<TreeNode, TreeNode>> index = indexOp.some();
     Option<TreeMap<TreeNode, TreeNode>> nodeMapOp = index.get(value);

--- a/src/test/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/core/nodeeditor/ReplaceRootNodeAt.java	Fri Mar 06 10:59:34 2015 +0900
+++ b/src/test/java/jp/ac/u_ryukyu/ie/cr/shoshi/jungle/core/nodeeditor/ReplaceRootNodeAt.java	Sun Mar 15 14:57:26 2015 +0900
@@ -17,7 +17,6 @@
 
   @Test
   public void ReplaceRootNodeAtTest() {
-      System.out.println("start");
     Jungle jungle = new DefaultJungle(null, "hogehoge", new DefaultTreeEditor(new DefaultTraverser()));
     jungle.createNewTree("tree");
     JungleTree tree = jungle.getTreeByName("tree");