<p>The SDK includes a full set of tools for developing and debugging application code and designing an application UI. You can read about the tools in the
<a href="{@docRoot}guide/developing/tools/index.html">Dev Guide</a> and access them in the <code><sdk>/tools/</code> directory.
<p>The tools package in this SDK includes updates from those provided in the previous SDK. The tools also require a different project structure. To use the new tools, you need to migrate your applications to the new development environment. For more information about how to migrate, see <a href="upgrading.html">Upgrading the SDK</a>.
<p>For more information about the new tools features, see the <a href="{@docRoot}sdk/RELEASENOTES.html">SDK Release Notes</a>.
<h4 id="system_images">Android Platforms</h4>
<p>This SDK includes multiple Android platform versions that you use to develop applications. For each version, both a fully compliant Android library and system image are provided. The table below lists the platform versions included in this SDK. For more information about a platform version — features, applications included, localizations, API changes, and so on — see its Version Notes. </p>
<td>Includes a standard Android 1.5 library and system image with a set of development applications. Does not include any external libraries (such as the Maps external library).</td>
<td>Includes a compliant Android 1.1 library and system image with a set of development applications. Also includes the Maps external library (due to legacy build system issues).</td>
</tr>
</table>
<h4 id="system_images">SDK Add-Ons</h4>
<p>An SDK add-on provides a development environment for an Android external library or a customized (but fully compliant) Android system image. This SDK includes the SDK add-on listed below. The Android system API Level required by the add-on is noted.</p>
<td>Includes the com.google.android.maps external library, a compliant
system image, a {@link android.location.Geocoder Geocoder}
backend service implementation, documentation, and sample code. </td>
</tr>
</table>
<h4>Sample Code and Applications</h4>
<p>You can look at a variety of tutorials and samples in the <a href="{@docRoot}guide/samples/index.html">Dev Guide</a> and access the sample code itself
in the <code><sdk>/platforms/android-1.5/samples/</code> directory of the SDK package. Note the new location — the SDK now includes multiple platform versions that you can develop against and each has its own sample code directory. </p>
<h4>Documentation</h4>
<p>The SDK package includes a full set of local documentation. To view it, open the <code><sdk>/documentation.html</code> file in a web browser. If you are developing in an IDE such as Eclipse, you can also view the reference documentation directly in the IDE. </p>
<p>The most current documentation is always available on the Android Developers site:</p>