diff --git a/dev/core/src/com/google/gwt/dev/ExternalPermutationWorkerFactory.java b/dev/core/src/com/google/gwt/dev/ExternalPermutationWorkerFactory.java
index 66b02fa..a4109e1 100644
--- a/dev/core/src/com/google/gwt/dev/ExternalPermutationWorkerFactory.java
+++ b/dev/core/src/com/google/gwt/dev/ExternalPermutationWorkerFactory.java
@@ -21,7 +21,7 @@
 import com.google.gwt.dev.jjs.UnifiedAst;
 import com.google.gwt.dev.util.FileBackedObject;
 import com.google.gwt.dev.util.Util;
-import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import java.io.BufferedReader;
 import java.io.EOFException;
@@ -254,7 +254,7 @@
 
     byte[] cookieBytes = new byte[16];
     random.nextBytes(cookieBytes);
-    String cookie = Utility.toHexString(cookieBytes);
+    String cookie = StringUtils.toHexString(cookieBytes);
 
     // Cook up the classpath, main class, and extra args
     args.addAll(Arrays.asList("-classpath",
diff --git a/dev/core/src/com/google/gwt/dev/util/Util.java b/dev/core/src/com/google/gwt/dev/util/Util.java
index 5a19a38..168cbaf 100644
--- a/dev/core/src/com/google/gwt/dev/util/Util.java
+++ b/dev/core/src/com/google/gwt/dev/util/Util.java
@@ -22,6 +22,7 @@
 import com.google.gwt.dev.util.log.speedtracer.SpeedTracerLogger;
 import com.google.gwt.dev.util.log.speedtracer.SpeedTracerLogger.Event;
 import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import org.w3c.dom.Attr;
 import org.w3c.dom.DOMException;
@@ -172,7 +173,7 @@
     for (int i = 0; i < contents.length; i++) {
       md5.update(contents[i]);
     }
-    return Utility.toHexString(md5.digest());
+    return StringUtils.toHexString(md5.digest());
   }
   
   public static void copy(InputStream is, OutputStream os) throws IOException {
@@ -437,11 +438,11 @@
   /**
    * A 4-digit hex result.
    * 
-   * @deprecated use {@link Utility#hex4(char, StringBuffer)} instead.
+   * @deprecated use {@link StringUtils#hex4(char, StringBuffer)} instead.
    */
   @Deprecated
   public static void hex4(char c, StringBuffer sb) {
-    Utility.hex4(c, sb);
+    StringUtils.hex4(c, sb);
   }
 
   /**
@@ -913,11 +914,11 @@
    * @param bytes byte array to convert
    * @return a string representation of the byte array as a series of
    *         hexadecimal characters
-   * @deprecated use {@link Utility#toHexString(byte[])} instead. 
+   * @deprecated use {@link StringUtils#toHexString(byte[])} instead. 
    */
   @Deprecated
   public static String toHexString(byte[] bytes) {
-    return Utility.toHexString(bytes);
+    return StringUtils.toHexString(bytes);
   }
 
   /**
diff --git a/dev/core/src/com/google/gwt/util/tools/Utility.java b/dev/core/src/com/google/gwt/util/tools/Utility.java
index fddb1ac..966be1e 100644
--- a/dev/core/src/com/google/gwt/util/tools/Utility.java
+++ b/dev/core/src/com/google/gwt/util/tools/Utility.java
@@ -32,8 +32,6 @@
 import java.net.Socket;
 import java.net.URI;
 import java.net.URL;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
@@ -44,24 +42,6 @@
  */
 public final class Utility {
 
-  /**
-   * Per thread MD5 instance.
-   */
-  private static final ThreadLocal<MessageDigest> perThreadMd5  =
-    new ThreadLocal<MessageDigest>() {
-      @Override
-      protected MessageDigest initialValue() {
-        try {
-          return MessageDigest.getInstance("MD5");
-        } catch (NoSuchAlgorithmException e) {
-          return null;
-        }
-      };
-  };
-
-  public static char[] HEX_CHARS = new char[] {
-    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
-    'E', 'F'};
 
   private static String sInstallPath = null;
 
@@ -255,29 +235,6 @@
   }
 
   /**
-   * Generate MD5 digest.
-   *
-   * @param input input data to be hashed.
-   * @return MD5 digest.
-   */
-  public static byte[] getMd5Digest(byte[] input) {
-    MessageDigest md5 = perThreadMd5.get();
-    md5.reset();
-    md5.update(input);
-    return md5.digest();
-  }
-
-  /**
-   * A 4-digit hex result.
-   */
-  public static void hex4(char c, StringBuffer sb) {
-    sb.append(HEX_CHARS[(c & 0xF000) >> 12]);
-    sb.append(HEX_CHARS[(c & 0x0F00) >> 8]);
-    sb.append(HEX_CHARS[(c & 0x00F0) >> 4]);
-    sb.append(HEX_CHARS[c & 0x000F]);
-  }
-
-  /**
    * Creates a randomly-named temporary directory.
    *
    * @param baseDir base directory to contain the new directory. May be
@@ -342,25 +299,6 @@
     }
   }
 
-  /**
-   * Returns a string representation of the byte array as a series of
-   * hexadecimal characters.
-   *
-   * @param bytes byte array to convert
-   * @return a string representation of the byte array as a series of
-   *         hexadecimal characters
-   */
-  public static String toHexString(byte[] bytes) {
-    char[] hexString = new char[2 * bytes.length];
-    int j = 0;
-    for (int i = 0; i < bytes.length; i++) {
-      hexString[j++] = HEX_CHARS[(bytes[i] & 0xF0) >> 4];
-      hexString[j++] = HEX_CHARS[bytes[i] & 0x0F];
-    }
-
-    return new String(hexString);
-  }
-
   public static void writeTemplateBinaryFile(File file, byte[] contents) throws IOException {
 
     FileOutputStream o = new FileOutputStream(file);
diff --git a/dev/core/src/com/google/gwt/util/tools/shared/Md5Utils.java b/dev/core/src/com/google/gwt/util/tools/shared/Md5Utils.java
new file mode 100644
index 0000000..d0af4e1
--- /dev/null
+++ b/dev/core/src/com/google/gwt/util/tools/shared/Md5Utils.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * 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.google.gwt.util.tools.shared;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+/**
+ * Utility class to generate MD5 hashes using per-thread MD5
+ * {@link MessageDigest} instance.
+ */
+public class Md5Utils {
+
+  /**
+   * Per thread MD5 instance.
+   */
+  private static final ThreadLocal<MessageDigest> perThreadMd5  =
+    new ThreadLocal<MessageDigest>() {
+      @Override
+      protected MessageDigest initialValue() {
+        try {
+          return MessageDigest.getInstance("MD5");
+        } catch (NoSuchAlgorithmException e) {
+          throw new RuntimeException("MD5 implementation not found", e);
+        }
+      };
+  };
+
+  /**
+   * Generate MD5 digest.
+   *
+   * @param input input data to be hashed.
+   * @return MD5 digest.
+   */
+  public static byte[] getMd5Digest(byte[] input) {
+    MessageDigest md5 = perThreadMd5.get();
+    md5.reset();
+    md5.update(input);
+    return md5.digest();
+  }
+}
diff --git a/dev/core/src/com/google/gwt/util/tools/shared/StringUtils.java b/dev/core/src/com/google/gwt/util/tools/shared/StringUtils.java
new file mode 100644
index 0000000..c7ffb3b
--- /dev/null
+++ b/dev/core/src/com/google/gwt/util/tools/shared/StringUtils.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2006 Google Inc.
+ *
+ * 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.google.gwt.util.tools.shared;
+
+/**
+ * String utility methods.
+ */
+public class StringUtils {
+
+  public static char[] HEX_CHARS = new char[] {
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
+    'E', 'F'};
+
+  /**
+   * A 4-digit hex result.
+   */
+  public static void hex4(char c, StringBuffer sb) {
+    sb.append(HEX_CHARS[(c & 0xF000) >> 12]);
+    sb.append(HEX_CHARS[(c & 0x0F00) >> 8]);
+    sb.append(HEX_CHARS[(c & 0x00F0) >> 4]);
+    sb.append(HEX_CHARS[c & 0x000F]);
+  }
+
+  /**
+   * Returns a string representation of the byte array as a series of
+   * hexadecimal characters.
+   *
+   * @param bytes byte array to convert
+   * @return a string representation of the byte array as a series of
+   *         hexadecimal characters
+   */
+  public static String toHexString(byte[] bytes) {
+    char[] hexString = new char[2 * bytes.length];
+    int j = 0;
+    for (int i = 0; i < bytes.length; i++) {
+      hexString[j++] = HEX_CHARS[(bytes[i] & 0xF0) >> 4];
+      hexString[j++] = HEX_CHARS[bytes[i] & 0x0F];
+    }
+    return new String(hexString);
+  }
+}
diff --git a/dev/core/src/com/google/gwt/util/tools/shared/package-info.java b/dev/core/src/com/google/gwt/util/tools/shared/package-info.java
new file mode 100644
index 0000000..201db87
--- /dev/null
+++ b/dev/core/src/com/google/gwt/util/tools/shared/package-info.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2011 Google Inc.
+ * 
+ * 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.
+ */
+
+/**
+ * Utility classes shared between gwt-dev and gwt-servlet.
+ */
+@com.google.gwt.util.PreventSpuriousRebuilds
+package com.google.gwt.util.tools.shared;
diff --git a/servlet/build.xml b/servlet/build.xml
index dcb9a83..f274e05 100755
--- a/servlet/build.xml
+++ b/servlet/build.xml
@@ -27,6 +27,7 @@
         <include name="com/google/gwt/dev/asm/**" />
         <include name="com/google/gwt/dev/util/Name*.class" />
         <include name="com/google/gwt/dev/util/StringKey.class" />
+        <include name="com/google/gwt/util/tools/shared/**" />
       </fileset>
       <fileset dir="${gwt.user.bin}">
         <exclude name="**/rebind/**" />
diff --git a/user/src/com/google/gwt/i18n/rebind/keygen/MD5KeyGenerator.java b/user/src/com/google/gwt/i18n/rebind/keygen/MD5KeyGenerator.java
index ff3bf48..71cc694 100644
--- a/user/src/com/google/gwt/i18n/rebind/keygen/MD5KeyGenerator.java
+++ b/user/src/com/google/gwt/i18n/rebind/keygen/MD5KeyGenerator.java
@@ -15,7 +15,7 @@
  */
 package com.google.gwt.i18n.rebind.keygen;
 
-import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import java.io.UnsupportedEncodingException;
 import java.security.MessageDigest;
@@ -55,6 +55,6 @@
     } catch (UnsupportedEncodingException e) {
       throw new RuntimeException("UTF-8 unsupported", e);
     }
-    return Utility.toHexString(md5.digest());
+    return StringUtils.toHexString(md5.digest());
   }
 }
diff --git a/user/src/com/google/gwt/i18n/server/keygen/MD5KeyGenerator.java b/user/src/com/google/gwt/i18n/server/keygen/MD5KeyGenerator.java
index 3849027..24c6e09 100644
--- a/user/src/com/google/gwt/i18n/server/keygen/MD5KeyGenerator.java
+++ b/user/src/com/google/gwt/i18n/server/keygen/MD5KeyGenerator.java
@@ -17,7 +17,7 @@
 
 import com.google.gwt.i18n.server.KeyGenerator;
 import com.google.gwt.i18n.server.Message;
-import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import java.io.UnsupportedEncodingException;
 import java.security.MessageDigest;
@@ -55,6 +55,6 @@
     } catch (UnsupportedEncodingException e) {
       throw new RuntimeException("UTF-8 unsupported", e);
     }
-    return Utility.toHexString(md5.digest());
+    return StringUtils.toHexString(md5.digest());
   }
 }
diff --git a/user/src/com/google/gwt/user/server/rpc/XsrfProtectedServiceServlet.java b/user/src/com/google/gwt/user/server/rpc/XsrfProtectedServiceServlet.java
index 5a6c062..43702cc 100644
--- a/user/src/com/google/gwt/user/server/rpc/XsrfProtectedServiceServlet.java
+++ b/user/src/com/google/gwt/user/server/rpc/XsrfProtectedServiceServlet.java
@@ -19,7 +19,8 @@
 import com.google.gwt.user.client.rpc.RpcTokenException;
 import com.google.gwt.user.client.rpc.XsrfToken;
 import com.google.gwt.user.server.Util;
-import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.Md5Utils;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import java.lang.reflect.Method;
 
@@ -111,8 +112,8 @@
           "Unable to verify XSRF cookie");
     }
 
-    String expectedToken = Utility.toHexString(
-        Utility.getMd5Digest(sessionCookie.getValue().getBytes()));
+    String expectedToken = StringUtils.toHexString(
+        Md5Utils.getMd5Digest(sessionCookie.getValue().getBytes()));
     XsrfToken xsrfToken = (XsrfToken) token;
 
     if (!expectedToken.equals(xsrfToken.getToken())) {
diff --git a/user/src/com/google/gwt/user/server/rpc/XsrfTokenServiceServlet.java b/user/src/com/google/gwt/user/server/rpc/XsrfTokenServiceServlet.java
index fa5343d..265b96f 100644
--- a/user/src/com/google/gwt/user/server/rpc/XsrfTokenServiceServlet.java
+++ b/user/src/com/google/gwt/user/server/rpc/XsrfTokenServiceServlet.java
@@ -19,7 +19,8 @@
 import com.google.gwt.user.client.rpc.XsrfToken;
 import com.google.gwt.user.client.rpc.XsrfTokenService;
 import com.google.gwt.user.server.Util;
-import com.google.gwt.util.tools.Utility;
+import com.google.gwt.util.tools.shared.Md5Utils;
+import com.google.gwt.util.tools.shared.StringUtils;
 
 import javax.servlet.http.Cookie;
 
@@ -195,7 +196,7 @@
           "Unable to generate XSRF cookie");
     }
     byte[] cookieBytes =  sessionCookie.getValue().getBytes();
-    return Utility.toHexString(Utility.getMd5Digest(cookieBytes));
+    return StringUtils.toHexString(Md5Utils.getMd5Digest(cookieBytes));
   }
 
   /**