diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/br/BrazilianStemmer.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/br/BrazilianStemmer.java
index 5cb4c714f68..24c5590c48d 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/br/BrazilianStemmer.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/br/BrazilianStemmer.java
@@ -1,5 +1,7 @@
 package org.apache.lucene.analysis.br;
 
+import java.util.Locale;
+
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
@@ -21,6 +23,7 @@ package org.apache.lucene.analysis.br;
  * A stemmer for Brazilian Portuguese words.
  */
 public class BrazilianStemmer {
+  private static final Locale locale = new Locale("pt", "BR");
 
 	/**
 	 * Changed term
@@ -243,7 +246,7 @@ public class BrazilianStemmer {
       return null ;
     }
 
-    value = value.toLowerCase() ;
+    value = value.toLowerCase(locale) ;
     for (j=0 ; j < value.length() ; j++) {
       if ((value.charAt(j) == 'á') ||
           (value.charAt(j) == 'â') ||
diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/de/GermanStemmer.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/de/GermanStemmer.java
index 90d01832631..805437c0065 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/de/GermanStemmer.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/de/GermanStemmer.java
@@ -1,4 +1,7 @@
 package org.apache.lucene.analysis.de;
+
+import java.util.Locale;
+
 // This file is encoded in UTF-8
 
 /*
@@ -37,6 +40,8 @@ public class GermanStemmer
      * Amount of characters that are removed with <tt>substitute()</tt> while stemming.
      */
     private int substCount = 0;
+    
+    private static final Locale locale = new Locale("de", "DE");
 
     /**
      * Stemms the given term to an unique <tt>discriminator</tt>.
@@ -47,7 +52,7 @@ public class GermanStemmer
     protected String stem( String term )
     {
       // Use lowercase for medium stemming.
-      term = term.toLowerCase();
+      term = term.toLowerCase(locale);
       if ( !isStemmable( term ) )
         return term;
       // Reset the StringBuilder.
diff --git a/lucene/analysis/common/src/java/org/apache/lucene/analysis/sinks/DateRecognizerSinkFilter.java b/lucene/analysis/common/src/java/org/apache/lucene/analysis/sinks/DateRecognizerSinkFilter.java
index efa4ec47653..59f02176349 100644
--- a/lucene/analysis/common/src/java/org/apache/lucene/analysis/sinks/DateRecognizerSinkFilter.java
+++ b/lucene/analysis/common/src/java/org/apache/lucene/analysis/sinks/DateRecognizerSinkFilter.java
@@ -20,6 +20,7 @@ package org.apache.lucene.analysis.sinks;
 import java.text.DateFormat;
 import java.text.ParseException;
 import java.util.Date;
+import java.util.Locale;
 
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.util.AttributeSource;
@@ -37,10 +38,11 @@ public class DateRecognizerSinkFilter extends TeeSinkTokenFilter.SinkFilter {
   protected CharTermAttribute termAtt;
   
   /**
-   * Uses {@link java.text.SimpleDateFormat#getDateInstance()} as the {@link java.text.DateFormat} object.
+   * Uses {@link java.text.SimpleDateFormat#getDateInstance(DateFormat.DEFAULT, Locale.ROOT)} as 
+   * the {@link java.text.DateFormat} object.
    */
   public DateRecognizerSinkFilter() {
-    this(DateFormat.getDateInstance());
+    this(DateFormat.getDateInstance(DateFormat.DEFAULT, Locale.ROOT));
   }
   
   public DateRecognizerSinkFilter(DateFormat dateFormat) {
diff --git a/lucene/analysis/common/src/test/org/apache/lucene/analysis/util/TestCharArrayIterator.java b/lucene/analysis/common/src/test/org/apache/lucene/analysis/util/TestCharArrayIterator.java
index ed8e641e63e..cbabcf157ad 100644
--- a/lucene/analysis/common/src/test/org/apache/lucene/analysis/util/TestCharArrayIterator.java
+++ b/lucene/analysis/common/src/test/org/apache/lucene/analysis/util/TestCharArrayIterator.java
@@ -32,7 +32,8 @@ public class TestCharArrayIterator extends LuceneTestCase {
   }
   
   public void testConsumeWordInstance() {
-    BreakIterator bi = BreakIterator.getWordInstance();
+    // we use the default locale, as its randomized by LuceneTestCase
+    BreakIterator bi = BreakIterator.getWordInstance(Locale.getDefault());
     CharArrayIterator ci = CharArrayIterator.newWordInstance();
     for (int i = 0; i < 10000; i++) {
       char text[] = _TestUtil.randomUnicodeString(random()).toCharArray();
@@ -43,7 +44,8 @@ public class TestCharArrayIterator extends LuceneTestCase {
   
   /* run this to test if your JRE is buggy
   public void testWordInstanceJREBUG() {
-    BreakIterator bi = BreakIterator.getWordInstance();
+    // we use the default locale, as its randomized by LuceneTestCase
+    BreakIterator bi = BreakIterator.getWordInstance(Locale.getDefault());
     Segment ci = new Segment();
     for (int i = 0; i < 10000; i++) {
       char text[] = _TestUtil.randomUnicodeString(random).toCharArray();
@@ -60,7 +62,8 @@ public class TestCharArrayIterator extends LuceneTestCase {
   }
   
   public void testConsumeSentenceInstance() {
-    BreakIterator bi = BreakIterator.getSentenceInstance();
+    // we use the default locale, as its randomized by LuceneTestCase
+    BreakIterator bi = BreakIterator.getSentenceInstance(Locale.getDefault());
     CharArrayIterator ci = CharArrayIterator.newSentenceInstance();
     for (int i = 0; i < 10000; i++) {
       char text[] = _TestUtil.randomUnicodeString(random()).toCharArray();
@@ -71,7 +74,8 @@ public class TestCharArrayIterator extends LuceneTestCase {
   
   /* run this to test if your JRE is buggy
   public void testSentenceInstanceJREBUG() {
-    BreakIterator bi = BreakIterator.getSentenceInstance();
+    // we use the default locale, as its randomized by LuceneTestCase
+    BreakIterator bi = BreakIterator.getSentenceInstance(Locale.getDefault());
     Segment ci = new Segment();
     for (int i = 0; i < 10000; i++) {
       char text[] = _TestUtil.randomUnicodeString(random).toCharArray();
diff --git a/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/TaskSequence.java b/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/TaskSequence.java
index 4f3abec4d41..f89ea26f2a4 100644
--- a/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/TaskSequence.java
+++ b/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/TaskSequence.java
@@ -429,7 +429,7 @@ public class TaskSequence extends PerfTask {
     sb.append(padd);
     sb.append(!letChildReport ? ">" : (parallel ? "]" : "}"));
     if (fixedTime) {
-      sb.append(" " + NumberFormat.getNumberInstance().format(runTimeSec) + "s");
+      sb.append(" " + NumberFormat.getNumberInstance(Locale.ROOT).format(runTimeSec) + "s");
     } else if (repetitions>1) {
       sb.append(" * " + repetitions);
     } else if (repetitions==REPEAT_EXHAUST) {
diff --git a/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java b/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java
index 9b9c73bf426..e023df005e6 100644
--- a/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java
+++ b/lucene/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java
@@ -18,6 +18,7 @@ package org.apache.lucene.benchmark.byTask.utils;
  */
 
 import java.text.NumberFormat;
+import java.util.Locale;
 
 /**
  * Formatting utilities (for reports).
@@ -25,9 +26,9 @@ import java.text.NumberFormat;
 public class Format {
 
   private static NumberFormat numFormat [] = { 
-    NumberFormat.getInstance(), 
-    NumberFormat.getInstance(),
-    NumberFormat.getInstance(),
+    NumberFormat.getInstance(Locale.ROOT), 
+    NumberFormat.getInstance(Locale.ROOT),
+    NumberFormat.getInstance(Locale.ROOT),
   };
   private static final String padd = "                                                 ";
   
diff --git a/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/QualityStats.java b/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/QualityStats.java
index 27f656a64bf..dcafbb4352d 100644
--- a/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/QualityStats.java
+++ b/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/QualityStats.java
@@ -19,6 +19,7 @@ package org.apache.lucene.benchmark.quality;
 import java.io.PrintWriter;
 import java.text.NumberFormat;
 import java.util.ArrayList;
+import java.util.Locale;
 
 /**
  * Results of quality benchmark run for a single query or for a set of queries.
@@ -141,7 +142,7 @@ public class QualityStats {
       logger.println(title);
     }
     prefix = prefix==null ? "" : prefix;
-    NumberFormat nf = NumberFormat.getInstance();
+    NumberFormat nf = NumberFormat.getInstance(Locale.ROOT);
     nf.setMaximumFractionDigits(3);
     nf.setMinimumFractionDigits(3);
     nf.setGroupingUsed(true);
diff --git a/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/utils/SubmissionReport.java b/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/utils/SubmissionReport.java
index 7ca49e1b4d6..b64f600c799 100644
--- a/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/utils/SubmissionReport.java
+++ b/lucene/benchmark/src/java/org/apache/lucene/benchmark/quality/utils/SubmissionReport.java
@@ -19,6 +19,7 @@ package org.apache.lucene.benchmark.quality.utils;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.text.NumberFormat;
+import java.util.Locale;
 
 import org.apache.lucene.benchmark.quality.QualityQuery;
 import org.apache.lucene.search.ScoreDoc;
@@ -45,7 +46,7 @@ public class SubmissionReport {
   public SubmissionReport (PrintWriter logger, String name) {
     this.logger = logger;
     this.name = name;
-    nf = NumberFormat.getInstance();
+    nf = NumberFormat.getInstance(Locale.ROOT);
     nf.setMaximumFractionDigits(4);
     nf.setMinimumFractionDigits(4);
   }
diff --git a/lucene/core/src/java/org/apache/lucene/index/CheckIndex.java b/lucene/core/src/java/org/apache/lucene/index/CheckIndex.java
index c6281bb723e..aa66348841b 100644
--- a/lucene/core/src/java/org/apache/lucene/index/CheckIndex.java
+++ b/lucene/core/src/java/org/apache/lucene/index/CheckIndex.java
@@ -25,6 +25,7 @@ import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 import org.apache.lucene.codecs.BlockTreeTermsReader;
@@ -340,7 +341,7 @@ public class CheckIndex {
    *  you only call this when the index is not opened by any
    *  writer. */
   public Status checkIndex(List<String> onlySegments) throws IOException {
-    NumberFormat nf = NumberFormat.getInstance();
+    NumberFormat nf = NumberFormat.getInstance(Locale.ROOT);
     SegmentInfos sis = new SegmentInfos();
     Status result = new Status();
     result.dir = dir;
diff --git a/lucene/core/src/java/org/apache/lucene/index/DocumentsWriterPerThread.java b/lucene/core/src/java/org/apache/lucene/index/DocumentsWriterPerThread.java
index ec393366a22..62ed5e9d395 100644
--- a/lucene/core/src/java/org/apache/lucene/index/DocumentsWriterPerThread.java
+++ b/lucene/core/src/java/org/apache/lucene/index/DocumentsWriterPerThread.java
@@ -20,6 +20,7 @@ package org.apache.lucene.index;
 import java.io.IOException;
 import java.text.NumberFormat;
 import java.util.HashSet;
+import java.util.Locale;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.codecs.Codec;
@@ -181,7 +182,7 @@ class DocumentsWriterPerThread {
   private int flushedDocCount;
   DocumentsWriterDeleteQueue deleteQueue;
   DeleteSlice deleteSlice;
-  private final NumberFormat nf = NumberFormat.getInstance();
+  private final NumberFormat nf = NumberFormat.getInstance(Locale.ROOT);
   final Allocator byteBlockAllocator;
 
   
diff --git a/lucene/facet/src/test/org/apache/lucene/util/encoding/EncodingSpeed.java b/lucene/facet/src/test/org/apache/lucene/util/encoding/EncodingSpeed.java
index a000b0cfdb8..bb7ca21f31d 100644
--- a/lucene/facet/src/test/org/apache/lucene/util/encoding/EncodingSpeed.java
+++ b/lucene/facet/src/test/org/apache/lucene/util/encoding/EncodingSpeed.java
@@ -157,7 +157,7 @@ public class EncodingSpeed {
   }
 
   static {
-    nf = NumberFormat.getInstance();
+    nf = NumberFormat.getInstance(Locale.ROOT);
     nf.setMaximumFractionDigits(4);
     nf.setMinimumFractionDigits(4);
 
diff --git a/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/precedence/TestPrecedenceQueryParser.java b/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/precedence/TestPrecedenceQueryParser.java
index 8926a4a7b4f..b542aa2b831 100644
--- a/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/precedence/TestPrecedenceQueryParser.java
+++ b/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/precedence/TestPrecedenceQueryParser.java
@@ -24,6 +24,7 @@ import java.util.Calendar;
 import java.util.Date;
 import java.util.GregorianCalendar;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 
 import org.apache.lucene.analysis.*;
@@ -385,13 +386,15 @@ public class TestPrecedenceQueryParser extends LuceneTestCase {
   }
 
   public String getDate(String s) throws Exception {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     return DateTools.dateToString(df.parse(s), DateTools.Resolution.DAY);
   }
 
   private String getLocalizedDate(int year, int month, int day,
       boolean extendLastDate) {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     Calendar calendar = new GregorianCalendar();
     calendar.set(year, month, day);
     if (extendLastDate) {
@@ -441,7 +444,8 @@ public class TestPrecedenceQueryParser extends LuceneTestCase {
 
   /** for testing DateTools support */
   private String getDate(String s, DateTools.Resolution resolution) throws Exception {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     return getDate(df.parse(s), resolution);
   }
 
diff --git a/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/standard/TestQPHelper.java b/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/standard/TestQPHelper.java
index 4f66aa856fd..dcc6dd79a27 100644
--- a/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/standard/TestQPHelper.java
+++ b/lucene/queryparser/src/test/org/apache/lucene/queryparser/flexible/standard/TestQPHelper.java
@@ -675,7 +675,8 @@ public class TestQPHelper extends LuceneTestCase {
   /** for testing DateTools support */
   private String getDate(String s, DateTools.Resolution resolution)
       throws Exception {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     return getDate(df.parse(s), resolution);
   }
 
@@ -693,7 +694,8 @@ public class TestQPHelper extends LuceneTestCase {
   }
 
   private String getLocalizedDate(int year, int month, int day) {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     Calendar calendar = new GregorianCalendar();
     calendar.clear();
     calendar.set(year, month, day);
diff --git a/lucene/queryparser/src/test/org/apache/lucene/queryparser/util/QueryParserTestBase.java b/lucene/queryparser/src/test/org/apache/lucene/queryparser/util/QueryParserTestBase.java
index 431ebc08812..e72d91f9da0 100644
--- a/lucene/queryparser/src/test/org/apache/lucene/queryparser/util/QueryParserTestBase.java
+++ b/lucene/queryparser/src/test/org/apache/lucene/queryparser/util/QueryParserTestBase.java
@@ -581,7 +581,8 @@ public abstract class QueryParserTestBase extends LuceneTestCase {
   
   /** for testing DateTools support */
   private String getDate(String s, DateTools.Resolution resolution) throws Exception {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     return getDate(df.parse(s), resolution);      
   }
   
@@ -591,7 +592,8 @@ public abstract class QueryParserTestBase extends LuceneTestCase {
   }
   
   private String getLocalizedDate(int year, int month, int day) {
-    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
+    // we use the default Locale since LuceneTestCase randomizes it
+    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());
     Calendar calendar = new GregorianCalendar();
     calendar.clear();
     calendar.set(year, month, day);
diff --git a/lucene/spatial/src/java/org/apache/lucene/spatial/prefix/tree/QuadPrefixTree.java b/lucene/spatial/src/java/org/apache/lucene/spatial/prefix/tree/QuadPrefixTree.java
index 2ed1c0ab73a..21f158d2183 100644
--- a/lucene/spatial/src/java/org/apache/lucene/spatial/prefix/tree/QuadPrefixTree.java
+++ b/lucene/spatial/src/java/org/apache/lucene/spatial/prefix/tree/QuadPrefixTree.java
@@ -28,6 +28,7 @@ import java.text.NumberFormat;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * @lucene.experimental
@@ -107,7 +108,7 @@ public class QuadPrefixTree extends SpatialPrefixTree {
   }
 
   public void printInfo() {
-    NumberFormat nf = NumberFormat.getNumberInstance();
+    NumberFormat nf = NumberFormat.getNumberInstance(Locale.ROOT);
     nf.setMaximumFractionDigits(5);
     nf.setMinimumFractionDigits(5);
     nf.setMinimumIntegerDigits(3);