With the Android M SDK (API 23), Google removed the Apache HTTP Client library. It was deprecated since API 22, and Google recommanded to use HttpURLConnection instead since API 9. While the classes are still bundled in Android 6 ROMs, it won’t be long until we see them completely go away.

Some applications are still relying on this library, and need to be updated to use the SDK 23, without having time/budget/whatever required to switch from HTTP Client. While I strongly recommend you to still take time to move to something else (there are many high-level libraries, like OkHttp or Ion, or you can use HttpURLConnection to keep a low-level access), there is a way to use the Apache library while using the SDK 23.

Current situation

The Android SDK is mainly a JAR of empty stubs, which allows the build system to assemble an APK depending on these stubs. But the JAR is not bundled in the APK. At runtime, Android will provide actual implementations of all these classes and their methods. That’s a rough explanation, but we don’t have to go more in-depth to explain the issue we have with the SDK 23.

In this new SDK, Google simply removed the stubs for the Apache HTTP Client library. As a result, any application using it doesn’t build anymore. But… an old APK still works on devices running on Android M. The explanation is simple: the stubs have been removed, but not the matching classes on the device. The solution seems obvious: we need to get back those stubs!

Fixing the problem on a Gradle project

Using the build-tools 23 and the SDK 23 (well, you won’t have the issue without it anyway), providing stubs for the Apache library is really easy. Simply add this command in the android section of your build.gradle:

build.gradle

android {
  useLibrary 'org.apache.http.legacy'
}

Rebuild, problem solved.

Other project types

If you’re not using Gradle, the solution is not much more complicated. Google is providing a JAR with the stubs you need. That’s the one used by Gradle. You can find it in your SDK: platforms/android-23/optional/org.apache.http.legacy.jar. Simply build against this JAR, and you’ll be fine.

In both cases, please remember to actually fix this by not using the Apache HTTP Client library any more as soon as possible, as it will probably be deleted in a future Android release.