diff --git a/docs/html/preview/api-overview.jd b/docs/html/preview/api-overview.jd
index 2fa029f..8ec2470 100644
--- a/docs/html/preview/api-overview.jd
+++ b/docs/html/preview/api-overview.jd
@@ -18,7 +18,6 @@
       <li><a href="#ART">New Android Runtime (ART)</a></li>
       <li><a href="#BehaviorNotifications">If your app implements notifications...</a></li>
       <li><a href="#BehaviorMediaControl">If your app uses RemoteControlClient...</a></li>
-      <li><a href="#BehaviorFullscreen">If your app uses fullScreenIntent...</a></li>
       <li><a href="#BehaviorGetRecentTasks">If your app uses ActivityManager.getRecentTasks()...</a></li>
     </ol>
   </li>
@@ -64,12 +63,13 @@
   <li><a href="#Power">Power Efficiency</a>
     <ol>
       <li><a href="#JobScheduler">Scheduling Jobs</a></li>
-      <li><a href="#PowerMeasurementTools">Developer tools and APIs for power measurement</a>
+      <li><a href="#PowerMeasurementTools">Developer tools for power measurement</a>
     </ol>
   </li>
   <li><a href="#Enterprise">Enterprise</a>
     <ol>
       <li><a href="#ManagedProvisioning">Managed provisioning</a></li>
+      <li><a href="#LockToAppMode">Lock-to-App mode</a></li>
     </ol>
   </li>
   <li><a href="#Printing">Printing Framework</a>
@@ -99,15 +99,15 @@
 </div>
 </div>
 
-<p>The L Developer Preview gives you an advance look at the upcoming release for
-the Android platform,
-which offers new features for users and app developers. This document provides
-an introduction to the most notable APIs.</p>
+<p>The L Developer Preview gives you an advance look at the upcoming release
+for the Android platform, which offers new features for users and app
+developers. This document provides an introduction to the most notable APIs.</p>
 
-<p>The L Developer Preview is intended for <strong>developer early adopters</strong> and
-<strong>testers</strong>. If you are interested in influencing the direction of the
-Android framework, <a href="{@docRoot}preview/setup-sdk.html">give the L
-Developer Preview a try</a> and send us your feedback!</p>
+<p>The L Developer Preview is intended for <strong>developer early
+adopters</strong> and <strong>testers</strong>. If you are interested in
+influencing the direction of the Android framework,
+<a href="{@docRoot}preview/setup-sdk.html">give the L Developer Preview a
+try</a> and send us your feedback!</p>
 
 <p class="caution"><strong>Caution:</strong> Do not not publish apps
 that use the L Developer Preview to the Google Play store.</p>
@@ -128,8 +128,8 @@
 <h3 id="ART">New Android Runtime (ART)</h3>
 
 <p>The 4.4 release introduced a new, experimental Android runtime, ART. Under
-4.4, ART was optional, and the default runtime remained Dalvik. With the L Developer Preview, ART is
-now the default runtime.</p>
+4.4, ART was optional, and the default runtime remained Dalvik. With the L
+Developer Preview, ART is now the default runtime.</p>
 
 <p>For an overview of ART's new features, see
 <a href="https://source.android.com/devices/tech/dalvik/art.html">Introducing
@@ -163,6 +163,15 @@
 backgrounds to match the new material design widgets. Make sure that all your
 notifications look right with the new color scheme:</p>
 
+<div class="figure" style="width:220px">
+  <img src="images/hun-example.png"
+    srcset="images/hun-example@2x.png 2x"
+    alt="" width="220" height="372" id="figure1" />
+  <p class="img-caption">
+    <strong>Figure 1.</strong> Fullscreen activity showing a heads-up notification
+  </p>
+</div>
+
 <ul>
 
   <li>Update or remove assets that involve color.</li>
@@ -179,39 +188,48 @@
 <p>If you are currently adding sounds and vibrations to your notifications by
 using the {@link android.media.Ringtone}, {@link android.media.MediaPlayer},
 or {@link android.os.Vibrator} classes, remove this code so that
-the system can present notifications correctly in <a href="#DoNotDisturb">Do Not Disturb</a> mode.
-Instead, use the {@link android.app.Notification.Builder} methods instead to add
-sounds and vibration.</p>
+the system can present notifications correctly in <a href="#DoNotDisturb">Do Not Disturb</a> mode. Instead, use the {@link android.app.Notification.Builder} methods instead to add sounds and vibration.</p>
+
+<p>Notifications now appear in a small floating window
+(also called a <em>heads-up notification</em>) when the device is active
+(that is, the device is unlocked and its screen is on). These notifications
+appear similar to the compact form of your notification, except that the
+heads-up notification also shows action buttons. Users can act on, or dismiss,
+a heads-up notification without leaving the current app.</p>
+
+<p>Examples of conditions that may trigger heads-up notifications include:</p>
+
+<ul>
+  <li>The user's activity is in fullscreen mode (the app uses
+{@link android.app.Notification#fullScreenIntent}), or</li>
+  <li>The notification has high priority and uses ringtones or
+    vibrations</li>
+</ul>
+
+<p>If your app implements notifications under those scenarios, make sure that
+heads-up notifications are presented correctly.</p>
 
 <h3 id="BehaviorMediaControl">If your app uses RemoteControlClient...</h3>
 
-<p>Lockscreens in the L Developer Preview do not show transport controls for your
-{@link android.media.RemoteControlClient}. Instead, your app can provide
-media playback control from the lockscreen through a media notification. This
+<p>Lockscreens in the L Developer Preview do not show transport controls for
+your {@link android.media.RemoteControlClient}. Instead, your app can provide
+media playback control from the lockscreen through a notification. This
 gives your app more control over the presentation of media buttons, while
 providing a consistent experience for users across the lockscreen and
 unlocked device.</p>
 
+<p>The L Developer Preview introduces a new {@code android.app.Notification.MediaStyle} template which is recommended for this purpose. {@code MediaStyle} converts notification actions that you added with {@link android.app.Notification.Builder#addAction(int, java.lang.CharSequence, android.app.PendingIntent) Notification.Builder.addAction()} into compact buttons embedded in your app's media playback notifications.</p>
+
+<p>If you are using the new
+{@code android.media.session.MediaSession} class (see <a href="#MediaPlaybackControl">Media Playback Control</a> below), attach your session
+token with {@code Notification.MediaStyle.setMediaToken()} to inform the
+system that this notification controls an ongoing media session.</p>
+
 <p>Call {@code
 Notification.Builder.setVisibility(Notification.VISIBILITY_PUBLIC)} to mark a
-notification as safe to display on the lockscreen (even when the lockscreen is
-secured with a PIN, pattern, or password). For more information, see
+notification as safe to show atop any lockscreen (secure or otherwise). For more information, see
 <a href="#LockscreenNotifications">Lockscreen Notifications</a>.</p>
 
-<h3 id="BehaviorFullscreen">If your app uses fullScreenIntent...</h3>
-
-<p>Notifications now appear in a small floating window if all these conditions
-are met:</p>
-
-<ul>
-  <li>The user’s activity is in fullscreen mode,</li>
-  <li>The screen is on, and</li>
-  <li>The device is unlocked</li>
-</ul>
-
-<p>If your app implements fullscreen activities, make sure that
-these heads-up notifications are presented correctly.</p>
-
 <h3 id="BehaviorGetRecentTasks">If your app uses ActivityManager.getRecentTasks()...</h3>
 
 <p>With the introduction of the new <em>concurrent documents and activities tasks</em> feature in the upcoming
@@ -230,7 +248,6 @@
 
 <h3 id="MaterialDesign">Material design support</h3>
 
-
 <p>The upcoming release adds support for Android's new <em>material</em> design
 style. You can create
 apps with material design that are visually dynamic and have UI element transitions
@@ -262,16 +279,17 @@
 
 <ul>
 <li>{@code VISIBILITY_PRIVATE}. Shows basic information, such as the
-notification’s icon, but hides the notification’s full content. If you want to
-provide a redacted public version of your notification for the system to display
-on a secure lockscreen, create a public notification object and put a reference
-to it in the private notification's {@code publicVersion} field.</li>
-<li>{@code VISIBILITY_PUBLIC}. Shows the notification’s full content. This is
-  the system default if visibility is left unspecified.</li>
-<li>{@code VISIBILITY_SECRET}. Shows only the most minimal information,
-excluding even the notification’s icon.</li>
+notification’s icon, but hides the notification’s full content.</li>
+<li>{@code VISIBILITY_PUBLIC}. Shows the notification’s full content.</li>
+<li>{@code VISIBILITY_SECRET}. Shows nothing, excluding even the
+notification’s icon.</li>
 </ul>
 
+<p>When {@code VISIBILITY_PRIVATE} is set, you can also provide a redacted
+version of the notification content that hides personal details. For example,
+an SMS app might display a notification that shows "You have 3 new text messages." but hides the message content and senders. To provide this alternative notification, first create the replacement notification using {@link android.app.Notification.Builder}. When you create the private notification object, attach
+the replacement notification to it through the {@code Notification.Builder.setPublicVersion()} method.</p>
+
 <h3 id="DoNotDisturb">Do Not Disturb mode</h3>
 
 <p>The L Developer Preview introduces a new <em>Do Not Disturb</em> mode. When
@@ -295,7 +313,7 @@
 your app is an alarm clock,
 you can tag the notification as an alarm so it will wake the user up even if the
 device is in <em>Do Not Disturb</em> mode. For more information, see <a
-href="NotificationsMetadata">Notifications metadata</a>.</p>
+href="#NotificationsMetadata">Notifications metadata</a>.</p>
 
 <h3 id="NotificationsMetadata">Notifications metadata</h3>
 <p>The L Developer Preview uses metadata associated with your app notifications
@@ -483,10 +501,9 @@
 
 <h3 id="DirectorySelection">Directory selection</h3>
 
-<p>The L Developer Preview extends the <a href="{@docRoot}guide/topics/providers/document-provider.html">Storage Access Framework</a> to let users
-select an entire directory, rather than individual files, to give your app
-read/write access to media files. When a directory is selected, your app also
-has access to all its child directories and content.</p>
+<p>The L Developer Preview extends the <a href="{@docRoot}guide/topics/providers/document-provider.html">Storage Access Framework</a> to let users select an entire directory, rather than individual files, to
+give your app read/write access to media files. When a directory is selected,
+your app also has access to all its child directories and content.</p>
 
 <p>To get the absolute paths to directories on external storage devices where
 applications can store media files, call the new
@@ -498,6 +515,13 @@
 permanent part of the device, and includes emulated external storage and
 physical media slots such as SD cards in battery compartments.</p>
 
+<p>You can bring up a system UI to allow the user to pick a directory subtree.
+To do so, send  {@code android.intent.action.OPEN_DOCUMENT_TREE} in an
+{@link android.content.Intent}. If the call is successful, the system displays
+the {@link android.provider.DocumentsProvider} instances installed on the
+device for the user to select. When the user selects a directory from this UI,
+the system returns a URI representing the selected directory tree.</p>
+
 <p>If you want to access a document in an existing directory, call the
 {@code android.provider.DocumentsContract.buildDocumentViaUri()} method.
 Pass the method a URI representing the path to the parent directory, and the
@@ -591,9 +615,9 @@
 asynchronously at a later time or under specified conditions (such as when the
 device is charging). This is useful in such situations as:</p>
 <ul>
-  <li>The app has non-user-facing work that you want to defer until the unit is
-    plugged in.</li>
-  <li>The app has a task that requires network access (or requires a wifi
+  <li>The app has non-user-facing work that you can defer.</li>
+  <li>The app has work you'd prefer to do when the unit is plugged in.</li>
+  <li>The app has a task that requires network access (or requires a Wi-Fi
     connection).</li>
   <li>The app has a number of tasks that you want to run as a batch on a regular
    schedule.</li>
@@ -612,6 +636,7 @@
   <li>The device is charging</li>
   <li>The device is connected to an unmetered network</li>
   <li>The system deems the device to be idle</li>
+  <li>Completion with a minimum delay or within a specific deadline.</li>
 </ul>
 
 <p>For example, you can add code like this to run your task on an
@@ -627,7 +652,7 @@
 jobScheduler.schedule(uploadTask);
 </pre>
 
-<h3 id="PowerMeasurementTools">Developer tools and APIs for power measurement</h3>
+<h3 id="PowerMeasurementTools">Developer tools for power measurement</h3>
 <p>The L Developer Preview provides several new developer tools and APIs to help
 you better measure and understand your app's power usage.</p>
 
@@ -668,9 +693,9 @@
 <img src="images/battery_historian.png"
      srcset="images/battery_historian@2x.png 2x"
     alt="" width="440" height="240"
-    id="figure1" />
+    id="figure2" />
 <p class="img-caption">
-  <strong>Figure 1.</strong>HTML visualization generated by the Battery
+  <strong>Figure 2.</strong>HTML visualization generated by the Battery
       Historian tool.
 </p>
 
@@ -701,9 +726,9 @@
 <div class="figure" style="width:360px">
   <img src="images/managed_apps_launcher.png"
     srcset="images/managed_apps_launcher@2x.png 2x"
-    alt="" width="360" height="572" id="figure2" />
+    alt="" width="360" height="572" id="figure3" />
   <p class="img-caption">
-    <strong>Figure 2.</strong> Launcher screen showing managed apps (marked with
+    <strong>Figure 3.</strong> Launcher screen showing managed apps (marked with
     a lock badge)
   </p>
 </div>
@@ -742,6 +767,36 @@
 the managed apps visually prominent by appending a “work” badge to the icon
 drawable with {@code android.os.UserManager.getBadgeDrawableForUser()}.</p>
 
+<h3 id="LockToAppMode">Lock-to-App mode</h3>
+<p>The L Developer Preview introduces a new <em>Lock-to-App</em> mode that
+lets you temporarily restrict users from leaving your app or being interrupted
+by notifications. Once your app activates this mode, users will not be able to
+see notifications, access other apps, or return to the Home screen, until your
+app exits the mode.</p>
+
+<p>To prevent unauthorized usage, the device on which you want to activate
+this mode must have managed profiles or must be fully controlled by a device administrator (see <a href="#ManagedProvisioning">Managed Provisioning</a> for more information). Furthermore, the device or managed profile owner must
+authorize apps to use this mode by calling {@code android.app.admin.DevicePolicyManager.setLockTaskComponents()}.</p>
+
+<p>Before activating this mode in your app, verify that your activity is authorized by calling {@code DevicePolicyManager.isLockTaskPermitted()}.</p>
+
+<p>To activate <em>Lock-to-App</em> mode, call
+{@code android.app.Activity.startLockTask()} from your authorized activity.</p>
+
+<p>When <em>Lock-to-App</em> mode is active, the following behavior takes
+effect:</p>
+
+<ul>
+<li>The status bar is blank, and user notifications and status information is hidden.</li>
+<li>The Home and Recent Apps button is hidden.</li>
+<li>Other apps may not launch new activities.</li>
+<li>The current app may start new activities, as long as doing so does not
+create new tasks.</li>
+</ul>
+
+<p>The device will remain in this mode until an authorized activity calls
+{@code Activity.stopLockTask()}.
+
 <h2 id="Printing">Printing Framework</h2>
 
 <h3 id="PDFRender">Render PDF as bitmap</h3>
@@ -752,7 +807,7 @@
 obtain a page for rendering with {@code openPage()}, then call {@code render()}
 to turn the opened {@code PdfRenderer.Page} into a bitmap. You can also set
 additional parameters if you only want to convert a portion of the document into
-a bitmap image (for example, to implement <a href="http://en.wikipedia.org/wiki/Tiled_rendering">tile rendering</a> in order to zoom in on the document).</p>
+a bitmap image (for example, to implement <a href="http://en.wikipedia.org/wiki/Tiled_rendering">tiled rendering</a> in order to zoom in on the document).</p>
 
 <h2 id="TestingA11y">Testing &amp; Accessibility </h2>
 
@@ -796,8 +851,7 @@
 
 <ul>
 <li>{@code FEATURE_LEANBACK}. Declares that your app must be installed only on
-devices that support the <a href="{@docRoot}training/tv}">Android TV</a> user
-interface. Example:
+devices that support the <a href="{@docRoot}training/tv/index.html}">Android TV</a>user interface. Example:
 <pre>
 &lt;uses-feature android:name="android.software.leanback"
               android:required="true" /&gt;
diff --git a/docs/html/preview/images/hun-example.png b/docs/html/preview/images/hun-example.png
new file mode 100644
index 0000000..9613a92
--- /dev/null
+++ b/docs/html/preview/images/hun-example.png
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diff --git a/docs/html/preview/images/hun-example@2x.png b/docs/html/preview/images/hun-example@2x.png
new file mode 100644
index 0000000..3cb8f5b
--- /dev/null
+++ b/docs/html/preview/images/hun-example@2x.png
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diff --git a/docs/html/preview/images/managed_apps_launcher@2.png b/docs/html/preview/images/managed_apps_launcher@2x.png
similarity index 100%
rename from docs/html/preview/images/managed_apps_launcher@2.png
rename to docs/html/preview/images/managed_apps_launcher@2x.png
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