diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/lang/UCharacter.java b/libcore/icu/src/main/java/com/ibm/icu4jni/lang/UCharacter.java
index 2839ac3..dc351f4 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/lang/UCharacter.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/lang/UCharacter.java
@@ -18,7 +18,7 @@
 
 import java.lang.Character.UnicodeBlock;
 
-public class UCharacter {
+public final class UCharacter {
 
     public static native boolean isDefined(int codePoint);
     public static native boolean isDigit(int codePoint);
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/regex/NativeRegEx.java b/libcore/icu/src/main/java/com/ibm/icu4jni/regex/NativeRegEx.java
index bdfff5b..789c75b 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/regex/NativeRegEx.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/regex/NativeRegEx.java
@@ -16,7 +16,7 @@
 
 package com.ibm.icu4jni.regex;
 
-public class NativeRegEx {
+public final class NativeRegEx {
 
     /**
      * Opens (compiles) an ICU regular expression.
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/text/BreakIterator.java b/libcore/icu/src/main/java/com/ibm/icu4jni/text/BreakIterator.java
deleted file mode 100644
index aa925aa..0000000
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/text/BreakIterator.java
+++ /dev/null
@@ -1,105 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- *
- * Licensed 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.
- */
-
-package com.ibm.icu4jni.text;
-
-import com.ibm.icu4jni.util.Resources;
-import java.text.CharacterIterator;
-import java.text.StringCharacterIterator;
-import java.util.Locale;
-
-public abstract class BreakIterator implements Cloneable
-{
-    protected static final int BI_CHAR_INSTANCE = 1;
-    protected static final int BI_WORD_INSTANCE = 2;
-    protected static final int BI_LINE_INSTANCE = 3;
-    protected static final int BI_SENT_INSTANCE = 4;
-    
-    protected int type = 0;
-    
-    public static Locale[] getAvailableLocales() {
-        return Resources.localesFromStrings(NativeBreakIterator.getAvailableLocalesImpl());
-    }
-    
-    public static BreakIterator getCharacterInstance() {
-        int iter = NativeBreakIterator.getCharacterInstanceImpl("");
-        return new RuleBasedBreakIterator(iter, BI_CHAR_INSTANCE);
-    }
-
-    public static BreakIterator getCharacterInstance(Locale where) {
-        int iter = NativeBreakIterator.getCharacterInstanceImpl(where.toString());
-        return new RuleBasedBreakIterator(iter, BI_CHAR_INSTANCE);
-    }
-
-    public static BreakIterator getLineInstance() {
-        int iter = NativeBreakIterator.getLineInstanceImpl("");
-        return new RuleBasedBreakIterator(iter, BI_LINE_INSTANCE);
-    }
-    
-    public static BreakIterator getLineInstance(Locale where) {
-        int iter = NativeBreakIterator.getLineInstanceImpl(where.toString());
-        return new RuleBasedBreakIterator(iter, BI_LINE_INSTANCE);
-    }
-    
-    public static BreakIterator getSentenceInstance() {
-        int iter = NativeBreakIterator.getSentenceInstanceImpl("");
-        return new RuleBasedBreakIterator(iter, BI_SENT_INSTANCE);
-    }
-
-    public static BreakIterator getSentenceInstance(Locale where) {
-        int iter = NativeBreakIterator.getSentenceInstanceImpl(where.toString());
-        return new RuleBasedBreakIterator(iter, BI_SENT_INSTANCE);
-    }
-    
-    public static BreakIterator getWordInstance() {
-        int iter = NativeBreakIterator.getWordInstanceImpl("");
-        return new RuleBasedBreakIterator(iter, BI_WORD_INSTANCE);
-    }
-
-    public static BreakIterator getWordInstance(Locale where) {
-        int iter = NativeBreakIterator.getWordInstanceImpl(where.toString());
-        return new RuleBasedBreakIterator(iter, BI_WORD_INSTANCE);
-    }
-
-    public void setText(String newText) {
-        setText(new StringCharacterIterator(newText));
-    }
-
-    public abstract boolean isBoundary(int offset);
-
-    public abstract int preceding(int offset);
-    
-    public abstract Object clone();
-
-    public abstract int current();
-
-    public abstract int first();
-
-    public abstract int following(int offset);
-
-    public abstract CharacterIterator getText();
-
-    public abstract int last();
-
-    public abstract int next(int n);
-
-    public abstract int next();
-
-    public abstract int previous();
-
-    public abstract void setText(CharacterIterator newText);
-
-}
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeBreakIterator.java b/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeBreakIterator.java
index e318e47..161f542 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeBreakIterator.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeBreakIterator.java
@@ -16,39 +16,146 @@
 
 package com.ibm.icu4jni.text;
 
-final class NativeBreakIterator {
-    private NativeBreakIterator() {
+import com.ibm.icu4jni.util.Resources;
+import java.text.CharacterIterator;
+import java.text.StringCharacterIterator;
+import java.util.Locale;
+
+public final class NativeBreakIterator implements Cloneable {
+    // Acceptable values for the 'type' field.
+    private static final int BI_CHAR_INSTANCE = 1;
+    private static final int BI_WORD_INSTANCE = 2;
+    private static final int BI_LINE_INSTANCE = 3;
+    private static final int BI_SENT_INSTANCE = 4;
+
+    private final int addr;
+    private final int type;
+    private CharacterIterator charIter;
+
+    private NativeBreakIterator(int iterAddr, int type) {
+        this.addr = iterAddr;
+        this.type = type;
+        this.charIter = new StringCharacterIterator("");
     }
 
-    static native String[] getAvailableLocalesImpl();
+    @Override
+    public Object clone() {
+        int cloneAddr = cloneImpl(this.addr);
+        NativeBreakIterator clone = new NativeBreakIterator(cloneAddr, this.type);
+        // The RI doesn't clone the CharacterIterator.
+        clone.charIter = this.charIter;
+        return clone;
+    }
 
-    static native int getCharacterInstanceImpl(String locale);
-    
-    static native int getWordInstanceImpl(String locale);
-    
-    static native int getLineInstanceImpl(String locale);
-    
-    static native int getSentenceInstanceImpl(String locale);
+    @Override
+    public boolean equals(Object object) {
+        if (object == null || !(object instanceof NativeBreakIterator)) {
+            return false;
+        }
+        // TODO: is this sufficient? shouldn't we be checking the underlying rules?
+        NativeBreakIterator rhs = (NativeBreakIterator) object;
+        return type == rhs.type && charIter.equals(rhs.charIter);
+    }
 
-    static native void closeBreakIteratorImpl(int biaddress);
-    
-    static native void setTextImpl(int biaddress, String text);
-    
-    static native int cloneImpl(int biaddress);
-    
-    static native int precedingImpl(int biaddress, int offset);
+    @Override
+    public int hashCode() {
+        return 42; // No-one uses BreakIterator as a hash key.
+    }
 
-    static native boolean isBoundaryImpl(int biaddress, int offset);
+    @Override
+    protected void finalize() {
+        closeBreakIteratorImpl(this.addr);
+    }
 
-    static native int nextImpl(int biaddress, int n);
+    public int current() {
+        return currentImpl(this.addr);
+    }
 
-    static native int previousImpl(int biaddress);
+    public int first() {
+        return firstImpl(this.addr);
+    }
 
-    static native int currentImpl(int biaddress);
+    public int following(int offset) {
+        return followingImpl(this.addr, offset);
+    }
 
-    static native int firstImpl(int biaddress);
+    public CharacterIterator getText() {
+        int newLoc = currentImpl(this.addr);
+        this.charIter.setIndex(newLoc);
+        return this.charIter;
+    }
 
-    static native int followingImpl(int biaddress, int offset);
+    public int last() {
+        return lastImpl(this.addr);
+    }
 
-    static native int lastImpl(int biaddress);
+    public int next(int n) {
+        return nextImpl(this.addr, n);
+    }
+
+    public int next() {
+        return nextImpl(this.addr, 1);
+    }
+
+    public int previous() {
+        return previousImpl(this.addr);
+    }
+
+    public void setText(CharacterIterator newText) {
+        this.charIter = newText;
+        StringBuilder sb = new StringBuilder();
+        for (char c = newText.first(); c != CharacterIterator.DONE; c = newText.next()) {
+            sb.append(c);
+        }
+        setTextImpl(this.addr, sb.toString());
+    }
+
+    public void setText(String newText) {
+        setText(new StringCharacterIterator(newText));
+    }
+
+    public boolean isBoundary(int offset) {
+        return isBoundaryImpl(this.addr, offset);
+    }
+
+    public int preceding(int offset) {
+        return precedingImpl(this.addr, offset);
+    }
+
+    public static Locale[] getAvailableLocales() {
+        return Resources.localesFromStrings(getAvailableLocalesImpl());
+    }
+
+    public static NativeBreakIterator getCharacterInstance(Locale where) {
+        return new NativeBreakIterator(getCharacterInstanceImpl(where.toString()), BI_CHAR_INSTANCE);
+    }
+
+    public static NativeBreakIterator getLineInstance(Locale where) {
+        return new NativeBreakIterator(getLineInstanceImpl(where.toString()), BI_LINE_INSTANCE);
+    }
+
+    public static NativeBreakIterator getSentenceInstance(Locale where) {
+        return new NativeBreakIterator(getSentenceInstanceImpl(where.toString()), BI_SENT_INSTANCE);
+    }
+
+    public static NativeBreakIterator getWordInstance(Locale where) {
+        return new NativeBreakIterator(getWordInstanceImpl(where.toString()), BI_WORD_INSTANCE);
+    }
+
+    private static native String[] getAvailableLocalesImpl();
+    private static native int getCharacterInstanceImpl(String locale);
+    private static native int getWordInstanceImpl(String locale);
+    private static native int getLineInstanceImpl(String locale);
+    private static native int getSentenceInstanceImpl(String locale);
+    private static native void closeBreakIteratorImpl(int addr);
+    private static native void setTextImpl(int addr, String text);
+    private static native int cloneImpl(int addr);
+    private static native int precedingImpl(int addr, int offset);
+    private static native boolean isBoundaryImpl(int addr, int offset);
+    private static native int nextImpl(int addr, int n);
+    private static native int previousImpl(int addr);
+    private static native int currentImpl(int addr);
+    private static native int firstImpl(int addr);
+    private static native int followingImpl(int addr, int offset);
+    private static native int lastImpl(int addr);
 }
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeDecimalFormat.java b/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeDecimalFormat.java
index d46c2ec..6f751d5 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeDecimalFormat.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/text/NativeDecimalFormat.java
@@ -31,7 +31,7 @@
 import java.util.Currency;
 import java.util.Locale;
 
-public class NativeDecimalFormat {
+public final class NativeDecimalFormat {
     /**
      * Constants corresponding to the native type UNumberFormatSymbol, for setSymbol.
      */
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/text/RuleBasedBreakIterator.java b/libcore/icu/src/main/java/com/ibm/icu4jni/text/RuleBasedBreakIterator.java
deleted file mode 100644
index e532ac4..0000000
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/text/RuleBasedBreakIterator.java
+++ /dev/null
@@ -1,138 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- *
- * Licensed 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.
- */
-
-package com.ibm.icu4jni.text;
-
-import java.text.CharacterIterator;
-import java.text.StringCharacterIterator;
-
-public class RuleBasedBreakIterator extends BreakIterator {
-
-    private CharacterIterator charIter;
-    
-    private int addr;
-
-    RuleBasedBreakIterator(int iterAddr, int type) {
-        this.addr = iterAddr;
-        this.type = type;
-        this.charIter = new StringCharacterIterator("");
-    }
-    
-    @Override
-    public Object clone() {
-        int cloneAddr = NativeBreakIterator.cloneImpl(this.addr);
-        RuleBasedBreakIterator rbbi = 
-                new RuleBasedBreakIterator(cloneAddr, this.type);
-        
-        rbbi.charIter = this.charIter;
-        
-        return rbbi;
-    }
-
-    @Override
-    public boolean equals(Object object) {
-        if(object == null) {
-            return false;
-        }
-        
-        if(!(object instanceof RuleBasedBreakIterator)) {
-            return false;
-        }
-        
-        CharacterIterator iter = ((RuleBasedBreakIterator) object).charIter;
-        
-        boolean result = this.type == ((RuleBasedBreakIterator) object).type;
-        
-        return result && iter.equals(this.charIter);
-    }
-
-    @Override
-    public int hashCode() {
-        return 42; // No-one uses RuleBasedBreakIterator as a hash key.
-    }
-
-    @Override
-    public int current() {
-        return NativeBreakIterator.currentImpl(this.addr);
-    }
-
-    @Override
-    public int first() {
-        return NativeBreakIterator.firstImpl(this.addr);
-    }
-
-    @Override
-    public int following(int offset) {
-        return NativeBreakIterator.followingImpl(this.addr, offset);
-    }
-
-    @Override
-    public CharacterIterator getText() {
-        int newLoc = NativeBreakIterator.currentImpl(this.addr);
-        this.charIter.setIndex(newLoc);
-        return this.charIter;
-    }
-
-    @Override
-    public int last() {
-        return NativeBreakIterator.lastImpl(this.addr);
-    }
-    
-    @Override
-    public int next(int n) {
-        return NativeBreakIterator.nextImpl(this.addr, n);
-    }
-
-    @Override
-    public int next() {
-        return NativeBreakIterator.nextImpl(this.addr, 1);
-    }
-    
-    @Override
-    public int previous() {
-        return NativeBreakIterator.previousImpl(this.addr);
-    }
-
-    @Override
-    public void setText(CharacterIterator newText) {
-        this.charIter = newText;
-
-        StringBuilder sb = new StringBuilder();
-        
-        char c = newText.first();
-        while(c != CharacterIterator.DONE) {
-            sb.append(c);
-            c = newText.next();
-        }
-
-        NativeBreakIterator.setTextImpl(this.addr, sb.toString());
-    }
-
-    protected void finalize() {
-        NativeBreakIterator.closeBreakIteratorImpl(this.addr);
-    }
-
-    @Override
-    public boolean isBoundary(int offset) {
-        return NativeBreakIterator.isBoundaryImpl(this.addr, offset);
-    }
-
-    @Override
-    public int preceding(int offset) {
-        return NativeBreakIterator.precedingImpl(this.addr, offset);
-    }
-
-}
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/util/LocaleData.java b/libcore/icu/src/main/java/com/ibm/icu4jni/util/LocaleData.java
index 87f9bc2..109183d 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/util/LocaleData.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/util/LocaleData.java
@@ -26,7 +26,7 @@
  * in the case of arrays. If you ever expose any of these things to user code, you must give
  * them a clone rather than the original.
  */
-public class LocaleData {
+public final class LocaleData {
     public Integer firstDayOfWeek;
     public Integer minimalDaysInFirstWeek;
     
diff --git a/libcore/icu/src/main/java/com/ibm/icu4jni/util/Resources.java b/libcore/icu/src/main/java/com/ibm/icu4jni/util/Resources.java
index 4a91d62..aae2ff4 100644
--- a/libcore/icu/src/main/java/com/ibm/icu4jni/util/Resources.java
+++ b/libcore/icu/src/main/java/com/ibm/icu4jni/util/Resources.java
@@ -31,7 +31,7 @@
  *
  * TODO: move the LocaleData stuff into LocaleData and rename this class.
  */
-public class Resources {
+public final class Resources {
     // A cache for the locale-specific data.
     private static final HashMap<String, LocaleData> localeDataCache =
             new HashMap<String, LocaleData>();
diff --git a/libcore/text/src/main/java/java/text/BreakIterator.java b/libcore/text/src/main/java/java/text/BreakIterator.java
index 78870f0..55ef31d 100644
--- a/libcore/text/src/main/java/java/text/BreakIterator.java
+++ b/libcore/text/src/main/java/java/text/BreakIterator.java
@@ -21,8 +21,8 @@
 
 package java.text;
 
+import com.ibm.icu4jni.text.NativeBreakIterator;
 import java.util.Locale;
-
 import org.apache.harmony.text.internal.nls.Messages;
 
 /**
@@ -241,7 +241,7 @@
     private static final int SHORT_LENGTH = 2;
 
     // the wrapped ICU implementation
-    com.ibm.icu4jni.text.BreakIterator wrapped;
+    NativeBreakIterator wrapped;
 
     /**
      * Default constructor, just for invocation by a subclass.
@@ -253,7 +253,7 @@
     /*
      * wrapping constructor
      */
-    BreakIterator(com.ibm.icu4jni.text.BreakIterator iterator) {
+    BreakIterator(NativeBreakIterator iterator) {
         wrapped = iterator;
     }
 
@@ -263,7 +263,7 @@
      * @return all supported locales.
      */
     public static Locale[] getAvailableLocales() {
-        return com.ibm.icu4jni.text.BreakIterator.getAvailableLocales();
+        return NativeBreakIterator.getAvailableLocales();
     }
 
     /**
@@ -273,8 +273,7 @@
      * @return a new instance of {@code BreakIterator} using the default locale.
      */
     public static BreakIterator getCharacterInstance() {
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getCharacterInstance());
+        return getCharacterInstance(Locale.getDefault());
     }
 
     /**
@@ -286,12 +285,7 @@
      * @return a new instance of {@code BreakIterator} using the given locale.
      */
     public static BreakIterator getCharacterInstance(Locale where) {
-        if (where == null) {
-            throw new NullPointerException();
-        }
-
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getCharacterInstance(where));
+        return new RuleBasedBreakIterator(NativeBreakIterator.getCharacterInstance(where));
     }
 
     /**
@@ -301,8 +295,7 @@
      * @return a new instance of {@code BreakIterator} using the default locale.
      */
     public static BreakIterator getLineInstance() {
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getLineInstance());
+        return getLineInstance(Locale.getDefault());
     }
 
     /**
@@ -315,12 +308,7 @@
      * @throws NullPointerException if {@code where} is {@code null}.
      */
     public static BreakIterator getLineInstance(Locale where) {
-        if (where == null) {
-            throw new NullPointerException();
-        }
-
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getLineInstance(where));
+        return new RuleBasedBreakIterator(NativeBreakIterator.getLineInstance(where));
     }
 
     /**
@@ -330,8 +318,7 @@
      * @return a new instance of {@code BreakIterator} using the default locale.
      */
     public static BreakIterator getSentenceInstance() {
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getSentenceInstance());
+        return getSentenceInstance(Locale.getDefault());
     }
 
     /**
@@ -344,12 +331,7 @@
      * @throws NullPointerException if {@code where} is {@code null}.
      */
     public static BreakIterator getSentenceInstance(Locale where) {
-        if (where == null) {
-            throw new NullPointerException();
-        }
-
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getSentenceInstance(where));
+        return new RuleBasedBreakIterator(NativeBreakIterator.getSentenceInstance(where));
     }
 
     /**
@@ -359,8 +341,7 @@
      * @return a new instance of {@code BreakIterator} using the default locale.
      */
     public static BreakIterator getWordInstance() {
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getWordInstance());
+        return getWordInstance(Locale.getDefault());
     }
 
     /**
@@ -373,12 +354,7 @@
      * @throws NullPointerException if {@code where} is {@code null}.
      */
     public static BreakIterator getWordInstance(Locale where) {
-        if (where == null) {
-            throw new NullPointerException();
-        }
-
-        return new RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator
-                .getWordInstance(where));
+        return new RuleBasedBreakIterator(NativeBreakIterator.getWordInstance(where));
     }
 
     /**
@@ -521,7 +497,7 @@
     public Object clone() {
         try {
             BreakIterator cloned = (BreakIterator) super.clone();
-            cloned.wrapped = (com.ibm.icu4jni.text.BreakIterator) wrapped.clone();
+            cloned.wrapped = (NativeBreakIterator) wrapped.clone();
             return cloned;
         } catch (CloneNotSupportedException e) {
             throw new AssertionError(e); // android-changed
diff --git a/libcore/text/src/main/java/java/text/RuleBasedBreakIterator.java b/libcore/text/src/main/java/java/text/RuleBasedBreakIterator.java
index 2ca6f9b..ed8a7c1 100644
--- a/libcore/text/src/main/java/java/text/RuleBasedBreakIterator.java
+++ b/libcore/text/src/main/java/java/text/RuleBasedBreakIterator.java
@@ -21,17 +21,20 @@
 
 package java.text;
 
+import com.ibm.icu4jni.text.NativeBreakIterator;
+
 /*
- * Default implementation of BreakIterator, wrap
- * com.ibm.icu4jni.text.RuleBasedBreakIterator
- * 
+ * Default implementation of BreakIterator. Wraps com.ibm.icu4jni.text.NativeBreakIterator.
+ * We need this because BreakIterator.isBoundary and BreakIterator.preceding are non-abstract,
+ * and we don't have Java implementations of those methods (other than the current ones, which
+ * forward to the wrapped NativeBreakIterator).
  */
 class RuleBasedBreakIterator extends BreakIterator {
 
     /*
-     * Wrapping construction
+     * Wrapping constructor.
      */
-    RuleBasedBreakIterator(com.ibm.icu4jni.text.BreakIterator iterator) {
+    RuleBasedBreakIterator(NativeBreakIterator iterator) {
         super(iterator);
     }
 
@@ -201,9 +204,7 @@
     @Override
     public Object clone() {
         RuleBasedBreakIterator cloned = (RuleBasedBreakIterator) super.clone();
-        cloned.wrapped = (com.ibm.icu4jni.text.RuleBasedBreakIterator) wrapped
-                .clone();
+        cloned.wrapped = (NativeBreakIterator) wrapped.clone();
         return cloned;
     }
-
 }