diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/MappingCharFilter.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/MappingCharFilter.java
index e91dc36b417..5bd456bbc43 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/MappingCharFilter.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/MappingCharFilter.java
@@ -59,7 +59,7 @@ public class MappingCharFilter extends BaseCharFilter {
     cachedRootArcs = normMap.cachedRootArcs;
 
     if (map != null) {
-      fstReader = map.getBytesReader(0);
+      fstReader = map.getBytesReader();
     } else {
       fstReader = null;
     }
diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/NormalizeCharMap.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/NormalizeCharMap.java
index c22203a76a4..9203784101c 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/NormalizeCharMap.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/charfilter/NormalizeCharMap.java
@@ -49,7 +49,7 @@ public class NormalizeCharMap {
       try {
         // Pre-cache root arcs:
         final FST.Arc<CharsRef> scratchArc = new FST.Arc<CharsRef>();
-        final FST.BytesReader fstReader = map.getBytesReader(0);
+        final FST.BytesReader fstReader = map.getBytesReader();
         map.getFirstArc(scratchArc);
         if (FST.targetHasArcs(scratchArc)) {
           map.readFirstRealTargetArc(scratchArc.target, scratchArc, fstReader);
diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/synonym/SynonymFilter.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/synonym/SynonymFilter.java
index 2267ce2007c..bd871ea6646 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/synonym/SynonymFilter.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/synonym/SynonymFilter.java
@@ -263,7 +263,7 @@ public final class SynonymFilter extends TokenFilter {
     this.synonyms = synonyms;
     this.ignoreCase = ignoreCase;
     this.fst = synonyms.fst;
-    this.fstReader = fst.getBytesReader(0);
+    this.fstReader = fst.getBytesReader();
     if (fst == null) {
       throw new IllegalArgumentException("fst must be non-null");
     }
diff --git a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/JapaneseTokenizer.java b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/JapaneseTokenizer.java
index b03c80effc8..de203b9c449 100644
--- a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/JapaneseTokenizer.java
+++ b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/JapaneseTokenizer.java
@@ -201,10 +201,10 @@ public final class JapaneseTokenizer extends Tokenizer {
     characterDefinition = unkDictionary.getCharacterDefinition();
     this.userDictionary = userDictionary;
     costs = ConnectionCosts.getInstance();
-    fstReader = fst.getBytesReader(0);
+    fstReader = fst.getBytesReader();
     if (userDictionary != null) {
       userFST = userDictionary.getFST();
-      userFSTReader = userFST.getBytesReader(0);
+      userFSTReader = userFST.getBytesReader();
     } else {
       userFST = null;
       userFSTReader = null;
diff --git a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/TokenInfoFST.java b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/TokenInfoFST.java
index e7c20da60e8..c386910044c 100644
--- a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/TokenInfoFST.java
+++ b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/TokenInfoFST.java
@@ -54,7 +54,7 @@ public final class TokenInfoFST {
     FST.Arc<Long> firstArc = new FST.Arc<Long>();
     fst.getFirstArc(firstArc);
     FST.Arc<Long> arc = new FST.Arc<Long>();
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
     // TODO: jump to 3040, readNextRealArc to ceiling? (just be careful we don't add bugs)
     for (int i = 0; i < rootCache.length; i++) {
       if (fst.findTargetArc(0x3040 + i, firstArc, arc, fstReader) != null) {
@@ -83,8 +83,8 @@ public final class TokenInfoFST {
     return fst.getFirstArc(arc);
   }
 
-  public FST.BytesReader getBytesReader(int pos) {
-    return fst.getBytesReader(pos);
+  public FST.BytesReader getBytesReader() {
+    return fst.getBytesReader();
   }
   
   /** @lucene.internal for testing only */
diff --git a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/UserDictionary.java b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/UserDictionary.java
index ba23f53c933..3ff5e64a01a 100644
--- a/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/UserDictionary.java
+++ b/lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/UserDictionary.java
@@ -139,7 +139,7 @@ public final class UserDictionary implements Dictionary {
     TreeMap<Integer, int[]> result = new TreeMap<Integer, int[]>(); // index, [length, length...]
     boolean found = false; // true if we found any results
 
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
 
     FST.Arc<Long> arc = new FST.Arc<Long>();
     int end = off + len;
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java b/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java
index 5c8718e6937..32324bb0890 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java
@@ -833,7 +833,7 @@ public class BlockTreeTermsReader extends FieldsProducer {
         if (index == null) {
           fstReader = null;
         } else {
-          fstReader = index.getBytesReader(0);
+          fstReader = index.getBytesReader();
         }
 
         // TODO: if the automaton is "smallish" we really
@@ -1277,7 +1277,7 @@ public class BlockTreeTermsReader extends FieldsProducer {
         if (index == null) {
           fstReader = null;
         } else {
-          fstReader = index.getBytesReader(0);
+          fstReader = index.getBytesReader();
         }
 
         // Init w/ root block; don't use index since it may
diff --git a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
index 7e8f7b2087f..e5c45a97f6d 100644
--- a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
+++ b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
@@ -417,7 +417,7 @@ public final class FST<T> {
     cachedRootArcs = (Arc<T>[]) new Arc[0x80];
     final Arc<T> arc = new Arc<T>();
     getFirstArc(arc);
-    final BytesReader in = getBytesReader(0);
+    final BytesReader in = getBytesReader();
     if (targetHasArcs(arc)) {
       readFirstRealTargetArc(arc.target, arc, in);
       while(true) {
@@ -1246,22 +1246,12 @@ public final class FST<T> {
   /** Returns a {@link BytesReader} for this FST, positioned at
    *  position 0. */
   public BytesReader getBytesReader() {
-    return getBytesReader(0);
-  }
-
-  /** Returns a {@link BytesReader} for this FST, positioned at
-   *  the provided position. */
-  public BytesReader getBytesReader(long pos) {
-    // TODO: maybe re-use via ThreadLocal?
     BytesReader in;
     if (packed) {
       in = bytes.getForwardReader();
     } else {
       in = bytes.getReverseReader();
     }
-    if (pos != 0) {
-      in.setPosition(pos);
-    }
     return in;
   }
 
@@ -1448,7 +1438,7 @@ public final class FST<T> {
 
     Arc<T> arc = new Arc<T>();
 
-    final BytesReader r = getBytesReader(0);
+    final BytesReader r = getBytesReader();
 
     final int topN = Math.min(maxDerefNodes, inCounts.size());
 
diff --git a/lucene/core/src/java/org/apache/lucene/util/fst/FSTEnum.java b/lucene/core/src/java/org/apache/lucene/util/fst/FSTEnum.java
index 13be2f1c5ba..ea0c68d8f85 100644
--- a/lucene/core/src/java/org/apache/lucene/util/fst/FSTEnum.java
+++ b/lucene/core/src/java/org/apache/lucene/util/fst/FSTEnum.java
@@ -46,7 +46,7 @@ abstract class FSTEnum<T> {
    *  term before target.  */
   protected FSTEnum(FST<T> fst) {
     this.fst = fst;
-    fstReader = fst.getBytesReader(0);
+    fstReader = fst.getBytesReader();
     NO_OUTPUT = fst.outputs.getNoOutput();
     fst.getFirstArc(getArc(0));
     output[0] = NO_OUTPUT;
@@ -145,7 +145,7 @@ abstract class FSTEnum<T> {
         // Arcs are fixed array -- use binary search to find
         // the target.
 
-        final FST.BytesReader in = fst.getBytesReader(0);
+        final FST.BytesReader in = fst.getBytesReader();
         int low = arc.arcIdx;
         int high = arc.numArcs-1;
         int mid = 0;
@@ -284,7 +284,7 @@ abstract class FSTEnum<T> {
         // Arcs are fixed array -- use binary search to find
         // the target.
 
-        final FST.BytesReader in = fst.getBytesReader(0);
+        final FST.BytesReader in = fst.getBytesReader();
         int low = arc.arcIdx;
         int high = arc.numArcs-1;
         int mid = 0;
@@ -434,7 +434,7 @@ abstract class FSTEnum<T> {
     FST.Arc<T> arc = getArc(upto-1);
     int targetLabel = getTargetLabel();
 
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
 
     while(true) {
       //System.out.println("  cycle target=" + (targetLabel == -1 ? "-1" : (char) targetLabel));
diff --git a/lucene/core/src/java/org/apache/lucene/util/fst/Util.java b/lucene/core/src/java/org/apache/lucene/util/fst/Util.java
index b67165174af..9eed4b8eb56 100644
--- a/lucene/core/src/java/org/apache/lucene/util/fst/Util.java
+++ b/lucene/core/src/java/org/apache/lucene/util/fst/Util.java
@@ -39,7 +39,7 @@ public final class Util {
     // TODO: would be nice not to alloc this on every lookup
     final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
 
-    final BytesReader fstReader = fst.getBytesReader(0);
+    final BytesReader fstReader = fst.getBytesReader();
 
     // Accumulate output as we go
     T output = fst.outputs.getNoOutput();
@@ -64,7 +64,7 @@ public final class Util {
   public static<T> T get(FST<T> fst, BytesRef input) throws IOException {
     assert fst.inputType == FST.INPUT_TYPE.BYTE1;
 
-    final BytesReader fstReader = fst.getBytesReader(0);
+    final BytesReader fstReader = fst.getBytesReader();
 
     // TODO: would be nice not to alloc this on every lookup
     final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
@@ -101,7 +101,7 @@ public final class Util {
    *  fit this. */
   public static IntsRef getByOutput(FST<Long> fst, long targetOutput) throws IOException {
 
-    final BytesReader in = fst.getBytesReader(0);
+    final BytesReader in = fst.getBytesReader();
 
     // TODO: would be nice not to alloc this on every lookup
     FST.Arc<Long> arc = fst.getFirstArc(new FST.Arc<Long>());
@@ -285,7 +285,7 @@ public final class Util {
 
     public TopNSearcher(FST<T> fst, int topN, int maxQueueDepth, Comparator<T> comparator) {
       this.fst = fst;
-      this.bytesReader = fst.getBytesReader(0);
+      this.bytesReader = fst.getBytesReader();
       this.topN = topN;
       this.maxQueueDepth = maxQueueDepth;
       this.comparator = comparator;
@@ -374,7 +374,7 @@ public final class Util {
 
       //System.out.println("search topN=" + topN);
 
-      final BytesReader fstReader = fst.getBytesReader(0);
+      final BytesReader fstReader = fst.getBytesReader();
       final T NO_OUTPUT = fst.outputs.getNoOutput();
 
       // TODO: we could enable FST to sorting arcs by weight
@@ -597,7 +597,7 @@ public final class Util {
     emitDotState(out, "initial", "point", "white", "");
 
     final T NO_OUTPUT = fst.outputs.getNoOutput();
-    final BytesReader r = fst.getBytesReader(0);
+    final BytesReader r = fst.getBytesReader();
 
     // final FST.Arc<T> scratchArc = new FST.Arc<T>();
 
diff --git a/lucene/core/src/test/org/apache/lucene/util/fst/TestFSTs.java b/lucene/core/src/test/org/apache/lucene/util/fst/TestFSTs.java
index b81b15b1a86..5e041b26a6a 100644
--- a/lucene/core/src/test/org/apache/lucene/util/fst/TestFSTs.java
+++ b/lucene/core/src/test/org/apache/lucene/util/fst/TestFSTs.java
@@ -1033,7 +1033,7 @@ public class TestFSTs extends LuceneTestCase {
         throws IOException {
         if (FST.targetHasArcs(arc)) {
           int childCount = 0;
-          BytesReader fstReader = fst.getBytesReader(0);
+          BytesReader fstReader = fst.getBytesReader();
           for (arc = fst.readFirstTargetArc(arc, arc, fstReader);; 
                arc = fst.readNextArc(arc, fstReader), childCount++)
           {
@@ -1168,12 +1168,12 @@ public class TestFSTs extends LuceneTestCase {
     assertEquals(nothing, startArc.nextFinalOutput);
 
     FST.Arc<Long> arc = fst.readFirstTargetArc(startArc, new FST.Arc<Long>(),
-                                               fst.getBytesReader(0));
+                                               fst.getBytesReader());
     assertEquals('a', arc.label);
     assertEquals(17, arc.nextFinalOutput.longValue());
     assertTrue(arc.isFinal());
 
-    arc = fst.readNextArc(arc, fst.getBytesReader(0));
+    arc = fst.readNextArc(arc, fst.getBytesReader());
     assertEquals('b', arc.label);
     assertFalse(arc.isFinal());
     assertEquals(42, arc.output.longValue());
@@ -1303,7 +1303,7 @@ public class TestFSTs extends LuceneTestCase {
     //Util.toDot(fst, w, false, false);
     //w.close();
     
-    BytesReader reader = fst.getBytesReader(0);
+    BytesReader reader = fst.getBytesReader();
     
     //System.out.println("testing: " + allPrefixes.size() + " prefixes");
     for (String prefix : allPrefixes) {
@@ -1424,7 +1424,7 @@ public class TestFSTs extends LuceneTestCase {
     //Util.toDot(fst, w, false, false);
     //w.close();
     
-    BytesReader reader = fst.getBytesReader(0);
+    BytesReader reader = fst.getBytesReader();
     
     //System.out.println("testing: " + allPrefixes.size() + " prefixes");
     for (String prefix : allPrefixes) {
diff --git a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingSuggester.java b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingSuggester.java
index 552cfea245c..0bbbef90b07 100644
--- a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingSuggester.java
+++ b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingSuggester.java
@@ -587,7 +587,7 @@ public class AnalyzingSuggester extends Lookup {
 
       //System.out.println("  prefixPaths: " + prefixPaths.size());
 
-      BytesReader bytesReader = fst.getBytesReader(0);
+      BytesReader bytesReader = fst.getBytesReader();
 
       FST.Arc<Pair<Long,BytesRef>> scratchArc = new FST.Arc<Pair<Long,BytesRef>>();
 
diff --git a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/FSTUtil.java b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/FSTUtil.java
index 686ae3b59e8..3bb21c25a33 100644
--- a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/FSTUtil.java
+++ b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/FSTUtil.java
@@ -77,7 +77,7 @@ public class FSTUtil {
         new IntsRef()));
     
     final FST.Arc<T> scratchArc = new FST.Arc<T>();
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
     
     while (queue.size() != 0) {
       final Path<T> path = queue.remove(queue.size() - 1);
diff --git a/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/FSTCompletion.java b/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/FSTCompletion.java
index 8d8d8b7b3a8..eea10423442 100644
--- a/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/FSTCompletion.java
+++ b/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/FSTCompletion.java
@@ -139,7 +139,7 @@ public class FSTCompletion {
     try {
       List<Arc<Object>> rootArcs = new ArrayList<Arc<Object>>();
       Arc<Object> arc = automaton.getFirstArc(new Arc<Object>());
-      FST.BytesReader fstReader = automaton.getBytesReader(0);
+      FST.BytesReader fstReader = automaton.getBytesReader();
       automaton.readFirstTargetArc(arc, arc, fstReader);
       while (true) {
         rootArcs.add(new Arc<Object>().copyFrom(arc));
@@ -173,7 +173,7 @@ public class FSTCompletion {
     // Get the UTF-8 bytes representation of the input key.
     try {
       final FST.Arc<Object> scratch = new FST.Arc<Object>();
-      FST.BytesReader fstReader = automaton.getBytesReader(0);
+      FST.BytesReader fstReader = automaton.getBytesReader();
       for (; rootArcIndex < rootArcs.length; rootArcIndex++) {
         final FST.Arc<Object> rootArc = rootArcs[rootArcIndex];
         final FST.Arc<Object> arc = scratch.copyFrom(rootArc);
@@ -338,7 +338,7 @@ public class FSTCompletion {
     final int max = utf8.offset + utf8.length;
     // Cannot save as instance var since multiple threads
     // can use FSTCompletion at once...
-    final FST.BytesReader fstReader = automaton.getBytesReader(0);
+    final FST.BytesReader fstReader = automaton.getBytesReader();
     for (int i = utf8.offset; i < max; i++) {
       if (automaton.findTargetArc(utf8.bytes[i] & 0xff, arc, arc, fstReader) == null) {
         // No matching prefixes, return an empty result.
@@ -362,7 +362,7 @@ public class FSTCompletion {
     }
     assert output.offset == 0;
     output.bytes[output.length++] = (byte) arc.label;
-    FST.BytesReader fstReader = automaton.getBytesReader(0);
+    FST.BytesReader fstReader = automaton.getBytesReader();
     automaton.readFirstTargetArc(arc, arc, fstReader);
     while (true) {
       if (arc.label == FST.END_LABEL) {
diff --git a/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/WFSTCompletionLookup.java b/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/WFSTCompletionLookup.java
index 1a7ff36cd1c..e6d69621e0f 100644
--- a/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/WFSTCompletionLookup.java
+++ b/lucene/suggest/src/java/org/apache/lucene/search/suggest/fst/WFSTCompletionLookup.java
@@ -200,7 +200,7 @@ public class WFSTCompletionLookup extends Lookup {
   private Long lookupPrefix(BytesRef scratch, Arc<Long> arc) throws /*Bogus*/IOException {
     assert 0 == fst.outputs.getNoOutput().longValue();
     long output = 0;
-    BytesReader bytesReader = fst.getBytesReader(0);
+    BytesReader bytesReader = fst.getBytesReader();
     
     fst.getFirstArc(arc);
     
diff --git a/lucene/test-framework/src/java/org/apache/lucene/util/fst/FSTTester.java b/lucene/test-framework/src/java/org/apache/lucene/util/fst/FSTTester.java
index 4d3924d667d..b68e97ffb2a 100644
--- a/lucene/test-framework/src/java/org/apache/lucene/util/fst/FSTTester.java
+++ b/lucene/test-framework/src/java/org/apache/lucene/util/fst/FSTTester.java
@@ -204,7 +204,7 @@ public class FSTTester<T> {
     final FST.Arc<T> arc = fst.getFirstArc(new FST.Arc<T>());
     final T NO_OUTPUT = fst.outputs.getNoOutput();
     T output = NO_OUTPUT;
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
 
     for(int i=0;i<=term.length;i++) {
       final int label;
@@ -241,7 +241,7 @@ public class FSTTester<T> {
     in.offset = 0;
     final T NO_OUTPUT = fst.outputs.getNoOutput();
     T output = NO_OUTPUT;
-    final FST.BytesReader fstReader = fst.getBytesReader(0);
+    final FST.BytesReader fstReader = fst.getBytesReader();
 
     while(true) {
       // read all arcs: