v811_spc009/compatibility/cdd/3_software/3_1_managed-api-compatibility.md

3.1. Managed API Compatibility

The managed Dalvik bytecode execution environment is the primary vehicle for Android applications. The Android application programming interface (API) is the set of Android platform interfaces exposed to applications running in the managed runtime environment.

Device implementations:

• [C-0-1] MUST provide complete implementations, including all documented behaviors, of any documented API exposed by the Android SDK or any API decorated with the “@SystemApi” marker in the upstream Android source code.

• [C-0-2] MUST support/preserve all classes, methods, and associated elements marked by the TestApi annotation (@TestApi).

• [C-0-3] MUST NOT omit any managed APIs, alter API interfaces or signatures, deviate from the documented behavior, or include no-ops, except where specifically allowed by this Compatibility Definition.

• [C-0-4] MUST still keep the APIs present and behave in a reasonable way, even when some hardware features for which Android includes APIs are omitted. See section 7 for specific requirements for this scenario.

• [C-0-5] MUST NOT allow third-party apps to use non-SDK interfaces, which are defined as methods and fields in the Java language packages that are in the boot classpath in AOSP, and that do not form part of the public SDK. This includes APIs decorated with the @hide annotation but not with a @SystemAPI, as described in the SDK documents and private and package-private class members.

• [C-0-6] MUST ship with each and every non-SDK interface on the same restricted lists as provided via the greylist, greylist-max-o, greylist-max-p, and blacklist flags in prebuilts/runtime/appcompat/hiddenapi-flags.csv path for the appropriate API level branch in the AOSP.

• [C-0-7] MUST support the signed config dynamic update mechanism to remove non-SDK interfaces from a restricted list by embedding signed configuration in any APK, using the existing public keys present in AOSP.

  However they:

  • MAY, if a hidden API is absent or implemented differently on the device implementation, move the hidden API into the blacklist or omit it from all restricted lists (i.e. light-grey, dark-grey, black).
  • MAY, if a hidden API does not already exist in the AOSP, add the hidden API to any of the restricted lists (i.e. light-grey, dark-grey, black).

3.1.1. Android Extensions

Android supports extending the managed API surface of a particular API level by updating the extension version for that API level. The android.os.ext.SdkExtensions.getExtensionVersion(int apiLevel) API returns the extension version of the provided apiLevel, if there are extensions for that API level.

Android device implementations:

• [C-0-1] MUST preload the AOSP implementation of both the shared library ExtShared and services ExtServices with versions greater than or equal to the minimum versions allowed per each API level. For example, Android 7.0 device implementations, running API level 24 MUST include at least version 1.

• [C-0-2] MUST only return valid extension version number that have been defined by the AOSP.

• [C-0-3] MUST support all the APIs defined by the extension versions returned by android.os.ext.SdkExtensions.getExtensionVersion(int apiLevel) in the same manner as other managed APIs are supported, following the requirements in section 3.1.

3.1.2. Android Library

Due to Apache HTTP client deprecation, device implementations:

• [C-0-1] MUST NOT place the org.apache.http.legacy library in the bootclasspath.
• [C-0-2] MUST add the org.apache.http.legacy library to the application classpath only when the app satisfies one of the following conditions:
  • Targets API level 28 or lower.
  • Declares in its manifest that it needs the library by setting the android:name attribute of <uses-library> to org.apache.http.legacy.

The AOSP implementation meets these requirements.