Android Hidden APIs are classes, methods and resources that Google hides from you because of stability reason. These features are hidden because they may be changed on next API version.

The internal APIs are located in package com.android.internal and available in the framework.jar, while the hidden APIs are located in the android.jar file with @hide javadoc attribute. Now you know the difference. But I will refer to both as hidden APIs.

This repo contains custom android.jar which you can use to develop your app. However, if you urgently need to create your own android.jar, I also share you the Krabby Patty secret recipe here: Create Your Own Android Hidden APIs.

Use Custom android.jar

1. Download custom android.jar from Google Drive. We no longer upload jars to Google Drive — every developer can now generate one for any API level with the hiddenjar CLI. Build it, then continue from step 2.
2. Go to <SDK location>/platforms/.
3. Copy, paste and replace the downloaded hidden API file into this directory, e.g. android-30/android.jar.
4. Change compileSdkVersion and targetSdkVersion to 35 (for example).
5. Finally, rebuild your project.

Note: Higher compileSdkVersion and targetSdkVersion will be better.

Build Your Own Custom android.jar (CLI)

Don't want to wait for a prebuilt jar? This repo ships hiddenjar, a CLI that builds a custom android.jar straight from a running Android emulator or device — no rooting, no manual DEX juggling. It pulls the framework jars over adb, converts DEX to .class, merges them into the SDK android.jar, strips the merged classes to signature-only stubs (so Gradle's lint/unit-test mockable-jar step accepts the jar — see issue #46), and verifies the result actually compiles a hidden API before finishing.

Unlike the classic recipe, it merges the whole $BOOTCLASSPATH (including mainline/APEX modules such as Wi‑Fi, Bluetooth, connectivity, media), so hidden APIs that no longer live in framework.jar are included too.

Prerequisites

• A JDK (javac + jar) and adb — both standard with Android Studio. The macOS/Linux bash script also needs unzip; the Windows PowerShell script needs no unzip (it uses the JDK jar tool).
• A running emulator at API ≥ 34 (recommended) or a device. Older emulator images may ship a stripped framework.jar; the CLI detects that and tells you to use a newer image.
• dex-tools is downloaded and cached automatically on first run.

Option A — the hiddenjar script (macOS/Linux & Windows)

macOS / Linux — the bash script:

# Check your environment (adb, JDK, dex-tools, connected devices)
./cli/hiddenjar doctor

# Build against a running emulator/device (auto-detected); full mainline coverage
./cli/hiddenjar build --api 37

# Faster, framework.jar only (fewer hidden APIs)
./cli/hiddenjar build --only-framework

# Boot an AVD first, build, and install into the SDK (backs up android.jar.orig)
./cli/hiddenjar build --avd Pixel_10_API_37 --install

# Roll back to the stock SDK jar
./cli/hiddenjar restore --api 37

Windows — the native PowerShell script (cli\hiddenjar.ps1, no Git Bash / WSL required):

# Same commands & flags; runs on built-in Windows PowerShell or PowerShell 7+
powershell -ExecutionPolicy Bypass -File cli\hiddenjar.ps1 doctor
powershell -ExecutionPolicy Bypass -File cli\hiddenjar.ps1 build --api 37
powershell -ExecutionPolicy Bypass -File cli\hiddenjar.ps1 build --only-framework
powershell -ExecutionPolicy Bypass -File cli\hiddenjar.ps1 build --avd Pixel_10_API_37 --install
powershell -ExecutionPolicy Bypass -File cli\hiddenjar.ps1 restore --api 37

Common flags (both scripts): --serial <id>, --avd <name>, --api <n>, --sdk-dir <path>, --output <file>, --install, --only-framework, --keep-bodies, --dex-tools <dir>. Run the script with help for the full list.

Option B — the Gradle wrapper (macOS/Linux/Windows)

./gradlew hiddenJarDoctor
./gradlew buildHiddenJar -Papi=37                 # full build
./gradlew buildHiddenJar -Papi=37 -Pinstall       # build + install into the SDK
./gradlew buildHiddenJar -PonlyFramework          # framework.jar only
./gradlew restoreHiddenJar -Papi=37               # roll back

Value props: -Papi -Pserial -Pavd -Poutput -PsdkDir -PdexTools. Flag props: -PonlyFramework -Pinstall -Pkeep.

Windows: everything works natively — no Git Bash or WSL. The Gradle wrapper (Option B) auto-runs the PowerShell script on Windows and the bash script elsewhere, so gradlew buildHiddenJar -Papi=37 works from cmd/PowerShell. You only need a JDK and adb; set ANDROID_HOME if your SDK isn't at the default %LOCALAPPDATA%\Android\Sdk.

Note: A custom jar only unblocks compilation. At runtime, Android 9+ (API 28+) still enforces the non-SDK (hidden API) blocklist for non-system apps.

For the full method, findings, and design rationale, see docs/BUILD_CUSTOM_ANDROID_JAR_FROM_EMULATOR.md.

Resources Helper

If you plan to use only Android internal resources rather than internal classes or methods, do:

dependencies {
    implementation 'com.anggrayudi:android-hidden-api:X.Y'
}

Where X.Y is the library version:

All versions can be found here. To use SNAPSHOT version, you need to add this URL to the root Gradle:

allprojects {
    repositories {
        google()
        mavenCentral()
        // add this line
        maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
    }
}

Here's some example of accessing internal resources:

String accept = InternalAccessor.getString("accept");
float sbar_height = InternalAccessor.getDimension("status_bar_height");
int notif_color = InternalAccessor.getColor("config_defaultNotificationColor");

Contributing

If you have your own custom android.jar and want to add it to Google Drive, please create an issue. I will upload it.

Uploading jars is no longer needed — every developer can build their own with the hiddenjar CLI. Contributions to the CLI itself (new flags, fixes, wider API-level coverage) are very welcome via pull request.

License

Copyright 2015-2026 Anggrayudi Hardiannico A.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.