diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index 2066c42..53d0a10 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -702,3 +702,14 @@
     name: "timezone-host",
     srcs: [":timezone_host_files"],
 }
+
+// The source files that contain the UnsupportedAppUsage annotation and its dependencies.
+filegroup {
+    name: "unsupportedappusage_annotation_files",
+    srcs: [
+        "dalvik/src/main/java/dalvik/annotation/compat/UnsupportedAppUsage.java",
+        "dalvik/src/main/java/dalvik/system/VersionCodes.java",
+        "luni/src/main/java/libcore/api/CorePlatformApi.java",
+        "luni/src/main/java/libcore/api/IntraCoreApi.java",
+    ],
+}
\ No newline at end of file
diff --git a/expectations/Android.bp b/expectations/Android.bp
new file mode 100644
index 0000000..bf4a993
--- /dev/null
+++ b/expectations/Android.bp
@@ -0,0 +1,9 @@
+filegroup {
+    name: "libcore-expectations-knownfailures",
+    srcs: ["knownfailures.txt"],
+}
+
+filegroup {
+    name: "libcore-expectations-virtualdeviceknownfailures",
+    srcs: ["virtualdeviceknownfailures.txt"],
+}
diff --git a/luni/src/main/java/libcore/util/TimeZoneFinder.java b/luni/src/main/java/libcore/util/TimeZoneFinder.java
new file mode 100644
index 0000000..c98decd
--- /dev/null
+++ b/luni/src/main/java/libcore/util/TimeZoneFinder.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2017 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 libcore.util;
+
+import android.icu.util.TimeZone;
+
+import java.util.List;
+
+// Used by com.google.android.setupwizard.hiddenapi.reflection.TimeZoneFinderReflection
+// Used by org.robolectric.shadows.ShadowTimeZoneFinder
+// Used by org.robolectric.shadows.ShadowTimeZoneFinderTest
+/**
+ * A shim class over {@link libcore.timezone.TimeZoneFinder} which used to be in
+ * {@code libcore.util}. This class provides just enough API to keep robolectric and SUW
+ * (setup wizard) working util those have been updated to use replacement public SDK APIs or adjust
+ * to the new package. See http://b/119921242 and http://b/116544863.
+ * @hide
+ */
+@libcore.api.CorePlatformApi
+public final class TimeZoneFinder {
+
+    private static TimeZoneFinder instance;
+    private final libcore.timezone.TimeZoneFinder delegate;
+
+    private TimeZoneFinder(libcore.timezone.TimeZoneFinder delegate) {
+        this.delegate = delegate;
+    }
+
+    // Used by com.google.android.setupwizard.hiddenapi.reflection.TimeZoneFinderReflection
+    // Used by org.robolectric.shadows.ShadowTimeZoneFinderTest
+    /**
+     * Obtains an instance for use when resolving time zones. This method never returns
+     * {@code null}.
+     */
+    @libcore.api.CorePlatformApi
+    public static TimeZoneFinder getInstance() {
+        synchronized(TimeZoneFinder.class) {
+            if (instance == null) {
+                instance = new TimeZoneFinder(libcore.timezone.TimeZoneFinder.getInstance());
+            }
+        }
+        return instance;
+    }
+
+    // Used by org.robolectric.shadows.ShadowTimeZoneFinder
+    /** Used to create an instance using an in-memory XML String instead of a file. */
+    public static TimeZoneFinder createInstanceForTests(String xml) {
+        return new TimeZoneFinder(libcore.timezone.TimeZoneFinder.createInstanceForTests(xml));
+    }
+
+    // Used by com.google.android.setupwizard.hiddenapi.reflection.TimeZoneFinderReflection
+    // Used by org.robolectric.shadows.ShadowTimeZoneFinderTest
+    /**
+     * Returns an immutable list of frozen ICU time zones known to be used in the specified country.
+     * If the country code is not recognized or there is an error during lookup this can return
+     * null. The TimeZones returned will never contain {@link TimeZone#UNKNOWN_ZONE}. This method
+     * can return an empty list in a case when the underlying data files reference only unknown
+     * zone IDs.
+     */
+    @libcore.api.CorePlatformApi
+    public List<TimeZone> lookupTimeZonesByCountry(String countryIso) {
+        return delegate.lookupTimeZonesByCountry(countryIso);
+    }
+}
diff --git a/luni/src/test/java/libcore/java/io/ObjectStreamClassTest.java b/luni/src/test/java/libcore/java/io/ObjectStreamClassTest.java
index 612b7d8..8bee284 100644
--- a/luni/src/test/java/libcore/java/io/ObjectStreamClassTest.java
+++ b/luni/src/test/java/libcore/java/io/ObjectStreamClassTest.java
@@ -16,6 +16,7 @@
 package libcore.java.io;
 
 import java.io.ObjectStreamClass;
+import java.io.ObjectStreamClass.DefaultSUIDCompatibilityListener;
 import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -31,6 +32,7 @@
 import org.junit.runners.MethodSorters;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
 @RunWith(JUnitParamsRunner.class)
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
@@ -99,8 +101,6 @@
         // The default SUID for the InheritStaticInitializer should be affected by the b/29064453
         // patch and so should differ between version <= 23 and version > 23.
         { InheritStaticInitializer.class, 4188245044387716731L, 992629205079295334L },
-
-
     };
   }
 
@@ -108,27 +108,46 @@
   @Test
   public void computeDefaultSUID_current(Class<?> clazz, long suid,
       @SuppressWarnings("unused") long suid23) {
-    checkSerialVersionUID(suid, clazz);
+    checkSerialVersionUID(suid, clazz, false);
   }
 
   @Parameters(method = "defaultSUIDs")
   @Test
   @TargetSdkVersion(23)
-  public void computeDefaultSUID_targetSdkVersion_23(Class<?> clazz,
-      @SuppressWarnings("unused") long suid, long suid23) {
-    checkSerialVersionUID(suid23, clazz);
+  public void computeDefaultSUID_targetSdkVersion_23(Class<?> clazz, long suid, long suid23) {
+    // If the suid and suid23 hashes are different then a warning is expected to be logged.
+    boolean expectedWarning = suid23 != suid;
+    checkSerialVersionUID(suid23, clazz, expectedWarning);
   }
 
-  private static void checkSerialVersionUID(long expectedSUID, Class<?> clazz) {
-    // Use reflection to access the private static computeDefaultSUID method.
+  private static void checkSerialVersionUID(
+      long expectedSUID, Class<?> clazz, boolean expectedWarning) {
+    // Use reflection to call the private static computeDefaultSUID method directly to avoid the
+    // caching performed by ObjectStreamClass.lookup(Class).
     long defaultSUID;
+    DefaultSUIDCompatibilityListener savedListener
+        = ObjectStreamClass.suidCompatibilityListener;
     try {
+      ObjectStreamClass.suidCompatibilityListener = (c, hash) -> {
+        // Delegate to the existing listener so that the warning is logged.
+        savedListener.warnDefaultSUIDTargetVersionDependent(clazz, hash);
+        if (expectedWarning) {
+          assertEquals(clazz, c);
+          assertEquals(expectedSUID, hash);
+        } else {
+          fail("Unexpected warning for " + c + " with defaultSUID " + hash);
+        }
+      };
+
       Method computeDefaultSUIDMethod =
           ObjectStreamClass.class.getDeclaredMethod("computeDefaultSUID", Class.class);
       computeDefaultSUIDMethod.setAccessible(true);
+
       defaultSUID = (Long) computeDefaultSUIDMethod.invoke(null, clazz);
     } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
       throw new IllegalStateException(e);
+    } finally {
+      ObjectStreamClass.suidCompatibilityListener = savedListener;
     }
     assertEquals(expectedSUID, defaultSUID);
   }
diff --git a/luni/src/test/java/libcore/java/lang/StringTest.java b/luni/src/test/java/libcore/java/lang/StringTest.java
index 7320d9a..c440ebe 100644
--- a/luni/src/test/java/libcore/java/lang/StringTest.java
+++ b/luni/src/test/java/libcore/java/lang/StringTest.java
@@ -781,4 +781,18 @@
             fail();
         } catch (NullPointerException expected) {}
     }
+
+    /**
+     * Check that String.format() does not throw when the default locale is invalid.
+     * http://b/129070579
+     */
+    public void testFormat_invalidLocale() {
+        Locale defaultLocale = Locale.getDefault();
+        try {
+            Locale.setDefault(new Locale("invalidLocale"));
+            String.format("%s", "");
+        } finally {
+            Locale.setDefault(defaultLocale);
+        }
+    }
 }
diff --git a/luni/src/test/java/libcore/libcore/icu/LocaleDataTest.java b/luni/src/test/java/libcore/libcore/icu/LocaleDataTest.java
index f5be28b..607397d 100644
--- a/luni/src/test/java/libcore/libcore/icu/LocaleDataTest.java
+++ b/luni/src/test/java/libcore/libcore/icu/LocaleDataTest.java
@@ -138,4 +138,12 @@
     LocaleData haw = LocaleData.get(new Locale("haw"));
     assertFalse(haw.shortDateFormat.isEmpty());
   }
+
+  /**
+   * Check that LocaleData.get() does not throw when the input locale is invalid.
+   * http://b/129070579
+   */
+  public void testInvalidLocale() {
+    LocaleData.get(new Locale("invalidLocale"));
+  }
 }
diff --git a/luni/src/test/java/libcore/libcore/util/TimeZoneFinderTest.java b/luni/src/test/java/libcore/libcore/util/TimeZoneFinderTest.java
new file mode 100644
index 0000000..aa1565b
--- /dev/null
+++ b/luni/src/test/java/libcore/libcore/util/TimeZoneFinderTest.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2017 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 libcore.libcore.util;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import android.icu.util.TimeZone;
+
+import java.util.List;
+import libcore.util.TimeZoneFinder;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+
+public class TimeZoneFinderTest {
+
+    @Test
+    public void getInstance() throws Exception {
+        TimeZoneFinder finder1 = TimeZoneFinder.getInstance();
+        TimeZoneFinder finder2 = TimeZoneFinder.getInstance();
+        assertSame(finder1, finder2);
+    }
+
+    @Test
+    public void lookupTimeZonesByCountry() throws Exception {
+        TimeZoneFinder finder = TimeZoneFinder.createInstanceForTests(
+                "<timezones ianaversion=\"2017b\">\n"
+                + "  <countryzones>\n"
+                + "    <country code=\"gb\" default=\"Europe/London\" everutc=\"y\">\n"
+                + "      <id>Europe/London</id>\n"
+                + "    </country>\n"
+                + "  </countryzones>\n"
+                + "</timezones>\n");
+
+        List<TimeZone> gbList = finder.lookupTimeZonesByCountry("gb");
+        assertEquals(1, gbList.size());
+        assertImmutableList(gbList);
+        assertImmutableTimeZone(gbList.get(0));
+
+        // Check country code normalization works too.
+        assertEquals(1, finder.lookupTimeZonesByCountry("GB").size());
+
+        assertNull(finder.lookupTimeZonesByCountry("unknown"));
+    }
+
+    private static void assertImmutableTimeZone(TimeZone timeZone) {
+        try {
+            timeZone.setRawOffset(1000);
+            fail();
+        } catch (UnsupportedOperationException expected) {
+        }
+    }
+
+    private static <X> void assertImmutableList(List<X> list) {
+        try {
+            list.add(null);
+            fail();
+        } catch (UnsupportedOperationException expected) {
+        }
+    }
+}
diff --git a/mmodules/core_platform_api/api/platform/current-api.txt b/mmodules/core_platform_api/api/platform/current-api.txt
index 225a28a..3686c20 100644
--- a/mmodules/core_platform_api/api/platform/current-api.txt
+++ b/mmodules/core_platform_api/api/platform/current-api.txt
@@ -800,10 +800,6 @@
 
 package java.lang {
 
-  public final class Byte extends java.lang.Number implements java.lang.Comparable<java.lang.Byte> {
-    method public static String toHexString(byte, boolean);
-  }
-
   public final class Class<T> implements java.lang.reflect.AnnotatedElement java.lang.reflect.GenericDeclaration java.io.Serializable java.lang.reflect.Type {
     method @dalvik.annotation.optimization.FastNative public java.lang.reflect.Field[] getDeclaredFieldsUnchecked(boolean);
     method @dalvik.annotation.optimization.FastNative public java.lang.reflect.Method[] getDeclaredMethodsUnchecked(boolean);
@@ -1247,6 +1243,11 @@
     method public static void sneakyThrow(Throwable);
   }
 
+  public final class TimeZoneFinder {
+    method public static libcore.util.TimeZoneFinder getInstance();
+    method public java.util.List<android.icu.util.TimeZone> lookupTimeZonesByCountry(String);
+  }
+
   public class XmlObjectFactory {
     method public static org.xml.sax.XMLReader newXMLReader();
     method public static org.xmlpull.v1.XmlPullParser newXmlPullParser();
diff --git a/non_openjdk_java_files.bp b/non_openjdk_java_files.bp
index 3e4083f..9d65f04 100644
--- a/non_openjdk_java_files.bp
+++ b/non_openjdk_java_files.bp
@@ -196,6 +196,7 @@
         "luni/src/main/java/libcore/util/Nullable.java",
         "luni/src/main/java/libcore/util/SneakyThrow.java",
         "luni/src/main/java/libcore/util/XmlObjectFactory.java",
+        "luni/src/main/java/libcore/util/TimeZoneFinder.java",
         "luni/src/main/java/libcore/util/ZoneInfo.java",
         "dalvik/src/main/java/org/apache/harmony/dalvik/NativeTestTarget.java",
         "dalvik/src/main/java/org/apache/harmony/dalvik/ddmc/Chunk.java",
diff --git a/ojluni/annotations/mmodule/java/lang/Byte.annotated.java b/ojluni/annotations/mmodule/java/lang/Byte.annotated.java
deleted file mode 100644
index 2d61598..0000000
--- a/ojluni/annotations/mmodule/java/lang/Byte.annotated.java
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-
-package java.lang;
-
-
-@SuppressWarnings({"unchecked", "deprecation", "all"})
-public final class Byte extends java.lang.Number implements java.lang.Comparable<java.lang.Byte> {
-
-public Byte(byte value) { throw new RuntimeException("Stub!"); }
-
-public Byte(java.lang.String s) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public static java.lang.String toString(byte b) { throw new RuntimeException("Stub!"); }
-
-public static java.lang.Byte valueOf(byte b) { throw new RuntimeException("Stub!"); }
-
-public static byte parseByte(java.lang.String s, int radix) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public static byte parseByte(java.lang.String s) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public static java.lang.Byte valueOf(java.lang.String s, int radix) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public static java.lang.Byte valueOf(java.lang.String s) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public static java.lang.Byte decode(java.lang.String nm) throws java.lang.NumberFormatException { throw new RuntimeException("Stub!"); }
-
-public byte byteValue() { throw new RuntimeException("Stub!"); }
-
-public short shortValue() { throw new RuntimeException("Stub!"); }
-
-public int intValue() { throw new RuntimeException("Stub!"); }
-
-public long longValue() { throw new RuntimeException("Stub!"); }
-
-public float floatValue() { throw new RuntimeException("Stub!"); }
-
-public double doubleValue() { throw new RuntimeException("Stub!"); }
-
-public java.lang.String toString() { throw new RuntimeException("Stub!"); }
-
-public int hashCode() { throw new RuntimeException("Stub!"); }
-
-public static int hashCode(byte value) { throw new RuntimeException("Stub!"); }
-
-public boolean equals(java.lang.Object obj) { throw new RuntimeException("Stub!"); }
-
-public int compareTo(java.lang.Byte anotherByte) { throw new RuntimeException("Stub!"); }
-
-public static int compare(byte x, byte y) { throw new RuntimeException("Stub!"); }
-
-public static int toUnsignedInt(byte x) { throw new RuntimeException("Stub!"); }
-
-public static long toUnsignedLong(byte x) { throw new RuntimeException("Stub!"); }
-
-@libcore.api.CorePlatformApi
-public static java.lang.String toHexString(byte b, boolean upperCase) { throw new RuntimeException("Stub!"); }
-
-public static final int BYTES = 1; // 0x1
-
-public static final byte MAX_VALUE = 127; // 0x7f
-
-public static final byte MIN_VALUE = -128; // 0xffffff80
-
-public static final int SIZE = 8; // 0x8
-
-public static final java.lang.Class<java.lang.Byte> TYPE;
-static { TYPE = null; }
-}
-
diff --git a/ojluni/src/main/java/java/io/ObjectStreamClass.java b/ojluni/src/main/java/java/io/ObjectStreamClass.java
index 7561aa8..10babed 100644
--- a/ojluni/src/main/java/java/io/ObjectStreamClass.java
+++ b/ojluni/src/main/java/java/io/ObjectStreamClass.java
@@ -1797,15 +1797,27 @@
                 }
             }
 
-            // Android-changed: Clinit serialization workaround b/29064453
+            // BEGIN Android-changed: Fix/log clinit serialization workaround b/29064453
             // Prior to SDK 24 hasStaticInitializer() would return true if the superclass had a
             // static initializer, that was contrary to the specification. In SDK 24 the default
             // behavior was corrected but the old behavior was preserved for apps that targeted 23
             // or below in order to maintain backwards compatibility.
+            //
+            // if (hasStaticInitializer(cl)) {
             boolean inheritStaticInitializer =
                 (VMRuntime.getRuntime().getTargetSdkVersion()
                 <= MAX_SDK_TARGET_FOR_CLINIT_UIDGEN_WORKAROUND);
+            boolean warnIncompatibleSUIDChange = false;
             if (hasStaticInitializer(cl, inheritStaticInitializer)) {
+                // If a static initializer was found but the current class does not have one then
+                // the class's default SUID will change if the app targets SDK > 24 so send a
+                // warning.
+                if (inheritStaticInitializer && !hasStaticInitializer(cl, false)) {
+                    // Defer until hash has been calculated so the warning message can give precise
+                    // instructions to the developer on how to fix the problems.
+                    warnIncompatibleSUIDChange = true;
+                }
+                // END Android-changed: Fix/log clinit serialization workaround b/29064453
                 dout.writeUTF("<clinit>");
                 dout.writeInt(Modifier.STATIC);
                 dout.writeUTF("()V");
@@ -1870,6 +1882,14 @@
             for (int i = Math.min(hashBytes.length, 8) - 1; i >= 0; i--) {
                 hash = (hash << 8) | (hashBytes[i] & 0xFF);
             }
+            // BEGIN Android-added: Fix/log clinit serialization workaround b/29064453
+            // ObjectStreamClass instances are cached per Class and caches its default
+            // serialVersionUID so it will only log one message per class per app process
+            // irrespective of the number of times the class is serialized.
+            if (warnIncompatibleSUIDChange) {
+                suidCompatibilityListener.warnDefaultSUIDTargetVersionDependent(cl, hash);
+            }
+            // END Android-added: Fix/log clinit serialization workaround b/29064453
             return hash;
         } catch (IOException ex) {
             throw new InternalError(ex);
@@ -1878,8 +1898,38 @@
         }
     }
 
-    // BEGIN Android-changed: Clinit serialization workaround b/29064453
-    /** Max SDK target version for which we use buggy hasStaticIntializier implementation. */
+    // BEGIN Android-changed: Fix/log clinit serialization workaround b/29064453
+    /**
+     * Created for testing as there is no nice way to detect when a message is logged.
+     *
+     * @hide
+     */
+    public interface DefaultSUIDCompatibilityListener {
+        /**
+         * Called when a class being serialized/deserialized relies on the default SUID computation
+         * (because it has no explicit {@code serialVersionUID} field) where that computation is
+         * dependent on the app's targetSdkVersion.
+         *
+         * @param clazz the clazz for which the default SUID is being computed.
+         * @param hash the computed value.
+         */
+        void warnDefaultSUIDTargetVersionDependent(Class<?> clazz, long hash);
+    }
+
+    /**
+     * Public and mutable for testing purposes.
+     *
+     * @hide
+     */
+    public static DefaultSUIDCompatibilityListener suidCompatibilityListener =
+        (clazz, hash) -> {
+            System.logW("Class " + clazz.getCanonicalName() + " relies on its default SUID which"
+                + " is dependent on the app's targetSdkVersion. To avoid problems during upgrade"
+                + " add the following to class " + clazz.getCanonicalName() + "\n"
+                + "    private static final long serialVersionUID = " + hash + "L;");
+        };
+
+    /** Max SDK target version for which we use buggy hasStaticInitializer implementation. */
     static final int MAX_SDK_TARGET_FOR_CLINIT_UIDGEN_WORKAROUND = 23;
 
     /**
@@ -1893,7 +1943,7 @@
      */
     private native static boolean hasStaticInitializer(
         Class<?> cl, boolean inheritStaticInitializer);
-    // END Android-changed: Clinit serialization workaround b/29064453
+    // END Android-changed: Fix/log clinit serialization workaround b/29064453
 
     /**
      * Class for computing and caching field/constructor/method signatures
diff --git a/ojluni/src/main/java/java/lang/Byte.java b/ojluni/src/main/java/java/lang/Byte.java
index e53899c..deb4ecb 100644
--- a/ojluni/src/main/java/java/lang/Byte.java
+++ b/ojluni/src/main/java/java/lang/Byte.java
@@ -25,6 +25,8 @@
 
 package java.lang;
 
+import libcore.util.HexEncoding;
+
 /**
  *
  * The {@code Byte} class wraps a value of primitive type {@code byte}
@@ -523,24 +525,8 @@
      * @hide
      */
     public static String toHexString(byte b, boolean upperCase) {
-        char[] digits = upperCase ? UPPER_CASE_DIGITS : DIGITS;
-        char[] buf = new char[2]; // We always want two digits.
-        buf[0] = digits[(b >> 4) & 0xf];
-        buf[1] = digits[b & 0xf];
-        return new String(0, 2, buf);
+        // This method currently retained because it is marked @UnsupportedAppUsage.
+        return HexEncoding.encodeToString(b, upperCase);
     }
-    private static final char[] DIGITS = {
-        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
-        'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
-        'u', 'v', 'w', 'x', 'y', 'z'
-    };
-
-    private static final char[] UPPER_CASE_DIGITS = {
-        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
-        'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
-        'U', 'V', 'W', 'X', 'Y', 'Z'
-    };
     // END Android-added: toHexString() for internal use.
 }