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Commit c79b6ecb authored by David Friedman's avatar David Friedman Committed by Android (Google) Code Review
Browse files

Merge "Docs: Behavior Changes doc for N Developer Preview 2" into mnc-mr-docs

parents c3cada0a d8ff49bd

docs/html/preview/behavior-changes.jd

+49 −3
Original line number Diff line number Diff line
@@ -31,6 +31,8 @@ page.image=images/cards/card-n-changes_2x.png 
  </li>

  <li><a href="#ndk">NDK Apps Linking to Platform Libraries</a></li>

  <li><a href="#afw">Android for Work</a></li>

  <li><a href="#annotations">Annotations Retention</a></li>

  <li><a href="#other">Other Important Points</a></li>

</ol>



<h2>See Also</h2>
@@ -184,7 +186,6 @@ page.image=images/cards/card-n-changes_2x.png 
  Optimizations</a>.

</p>





<h2 id="perm">Permissions Changes</h2>



<p>
@@ -467,7 +468,7 @@ JavaVM::AttachCurrentThread from &lt;jni.h&gt;. 


  <li>Reset password restrictions for device admins now apply to profile

  owners. Device admins can no longer use

  <code>DevicePolicyManager.resetPassword()</code> to clear passwords or change

  {@code DevicePolicyManager.resetPassword()} to clear passwords or change

  ones that are already set. Device admins can still set a password, but only

  when the device has no password, PIN, or pattern.

  </li>
@@ -497,7 +498,26 @@ JavaVM::AttachCurrentThread from &lt;jni.h&gt;. 
  <a href="{@docRoot}preview/features/afw.html">Android for Work Updates</a>.

</p>



<h2 id="other">Other important points</h2>

<h2 id="annotations">Annotations Retention</h2>



<p>

Android N fixes a bug where the visibility of annotations was being ignored.

This issue enabled the runtime to access annotations that it should not have been

able to. These annotations included:

</p>



<ul>

   <li>{@code VISIBILITY_BUILD}: Intended to be visible only at build time.</li>

   <li>{@code VISIBILITY_SYSTEM}: Intended to be visible at runtime, but only to the

   underlying system.</li>

</ul>



<p>

If your app has relied on this behavior, please add a retention policy to annotations that must

be available at runtime. You do so by using {@code @Retention(RetentionPolicy.RUNTIME)}.

</p>



<h2 id="other">Other Important Points</h2>



<ul>

<li>When an app is running on Android N, but targets a lower API level,
@@ -525,5 +545,31 @@ by changing font size (<strong>Setting</strong> > 
<strong>Display</strong> > <strong>Font size</strong>), and then restoring

the app from Recents.

</li>



<li>

Due to a bug in previous versions of Android, the system did not flag writing

to a TCP socket on the main thread as a strict-mode violation. Android N fixes this bug.

Apps that exhibit this behavior now throw an {@code android.os.NetworkOnMainThreadException}.

Generally, performing network operations on the main thread is a bad idea because these operations

usually have a high tail latency that causes ANRs and jank.

</li>



<li>

The {@code Debug.startMethodTracing()} family of methods now defaults to

storing output in your package-specific directory on shared storage,

instead of at the top level

of the SD card.  This means apps no longer need to request the {@code WRITE_EXTERNAL_STORAGE} permission to use these APIs.

</li>



<li>

Many platform APIs have now started checking for large payloads being sent

across {@link android.os.Binder} transactions, and the

system now rethrows {@code TransactionTooLargeExceptions}

as {@code RuntimeExceptions}, instead of silently logging or suppressing them.  One

common example is storing too much data in

{@link android.app.Activity#onSaveInstanceState Activity.onSaveInstanceState()},

which causes {@code ActivityThread.StopInfo} to throw a

{@code RuntimeException} when your app targets Android N.

</li>

</ul>