Initial Contribution
diff --git a/tools/preload/WritePreloadedClassFile.java b/tools/preload/WritePreloadedClassFile.java
new file mode 100644
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+++ b/tools/preload/WritePreloadedClassFile.java
@@ -0,0 +1,87 @@
+/*
+ * 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.
+ */
+
+import java.io.IOException;
+import java.io.Writer;
+import java.io.BufferedWriter;
+import java.io.OutputStreamWriter;
+import java.io.FileOutputStream;
+import java.nio.charset.Charset;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.List;
+
+/**
+ * Writes /java/android/preloaded-classes. Also updates LoadedClass.preloaded
+ * fields and writes over compiled log file.
+ */
+public class WritePreloadedClassFile {
+
+    private static final String PRELOADED_CLASS_FILE
+            = "java/android/preloaded-classes";
+
+    public static void main(String[] args)
+            throws IOException, ClassNotFoundException {
+        if (args.length != 1) {
+            System.err.println(
+                    "Usage: WritePreloadedClassFile [compiled log file]");
+            System.exit(0);
+        }
+
+        Root root = Root.fromFile(args[0]);
+
+        for (LoadedClass loadedClass : root.loadedClasses.values()) {
+            loadedClass.preloaded = false;
+        }
+
+        Writer out = new BufferedWriter(new OutputStreamWriter(
+                new FileOutputStream(PRELOADED_CLASS_FILE),
+                Charset.forName("US-ASCII")));
+
+        out.write("# Classes which are preloaded by " +
+                "com.android.internal.os.ZygoteInit.\n");
+        out.write("# Automatically generated by /tools/preload.\n");
+        out.write("# percent=" + Proc.PERCENTAGE_TO_PRELOAD + ", weight="
+                + ClassRank.SEQUENCE_WEIGHT
+                + ", bucket_size=" + ClassRank.BUCKET_SIZE
+                + "\n");
+
+        Set<LoadedClass> highestRanked = new TreeSet<LoadedClass>();
+        for (Proc proc : root.processes.values()) {
+            List<LoadedClass> highestForProc = proc.highestRankedClasses();
+
+            System.out.println(proc.name + ": " + highestForProc.size());
+
+            for (LoadedClass loadedClass : highestForProc) {
+                loadedClass.preloaded = true;
+            }
+            highestRanked.addAll(highestForProc);
+        }
+
+        for (LoadedClass loadedClass : highestRanked) {
+            out.write(loadedClass.name);
+            out.write('\n');
+        }
+
+        out.close();
+
+        System.out.println(highestRanked.size()
+                + " classes will be preloaded.");
+
+        // Update data to reflect LoadedClass.preloaded changes.
+        root.toFile(args[0]);
+    }
+}