Index: lucene/facet/src/test/org/apache/lucene/facet/taxonomy/TestTaxonomyCombined.java
===================================================================
--- lucene/facet/src/test/org/apache/lucene/facet/taxonomy/TestTaxonomyCombined.java	(revision 1438974)
+++ lucene/facet/src/test/org/apache/lucene/facet/taxonomy/TestTaxonomyCombined.java	(working copy)
@@ -1132,6 +1132,23 @@
     dir.close();
   }
 
+  @Test
+  public void testEmptyString() throws Exception {
+    Directory dir = newDirectory();
+    DirectoryTaxonomyWriter writer = new DirectoryTaxonomyWriter(dir);
+    CategoryPath cp1 = new CategoryPath("test");
+    int ord1 = writer.addCategory(cp1);
+    CategoryPath cp2 = new CategoryPath("test", "");
+    int ord2 = writer.addCategory(cp2);
+    assertTrue(ord1 != ord2);
+    TaxonomyReader reader = new DirectoryTaxonomyReader(writer);
+    writer.close();
+    assertEquals(cp1, reader.getPath(ord1));
+    assertEquals(cp2, reader.getPath(ord2));
+    reader.close();
+    dir.close();
+  }
+
 //  TODO (Facet): test multiple readers, one writer. Have the multiple readers
 //  using the same object (simulating threads) or different objects
 //  (simulating processes).
Index: lucene/facet/src/java/org/apache/lucene/facet/taxonomy/CategoryPath.java
===================================================================
--- lucene/facet/src/java/org/apache/lucene/facet/taxonomy/CategoryPath.java	(revision 1438974)
+++ lucene/facet/src/java/org/apache/lucene/facet/taxonomy/CategoryPath.java	(working copy)
@@ -1,24 +1,26 @@
 package org.apache.lucene.facet.taxonomy;
 
-import org.apache.lucene.util.Constants;
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
 
+import java.util.ArrayList;
+import java.util.List;
 
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+import org.apache.lucene.util.Constants;
 
 /**
  * Holds a sequence of string components, specifying the hierarchical name of a
@@ -82,7 +84,19 @@
 
   /** Construct from a given path, separating path components with {@code delimiter}. */
   public CategoryPath(final String pathString, final char delimiter) {
-    String[] comps = pathString.split(Character.toString(delimiter));
+    int upto = 0;
+    List<String> compsList = new ArrayList<String>();
+    while (true) {
+      int next = pathString.indexOf(delimiter, upto);
+      if (next == -1) {
+        compsList.add(pathString.substring(upto));
+        break;
+      } else {
+        compsList.add(pathString.substring(upto, next));
+        upto = next+1;
+      }
+    }
+    String[] comps = compsList.toArray(new String[compsList.size()]);
     if (comps.length == 1 && comps[0].isEmpty()) {
       components = EMPTY.components;
       length = 0;