D8.jar Download Guide

java -jar d8.jar --help

Basic example – Convert a JAR of class files into one or more DEX files:

java -jar d8.jar myapp.jar --output output_dir/

Advanced options:

java -jar d8.jar \
  --lib android.jar \        # Android framework classes
  --release \                # Optimized release mode
  --min-api 21 \             # Target Android API level
  --no-desugaring \          # Skip Java language desugaring
  --intermediate \           # For incremental compilation
  input_classes/ \
  --output output_dex/

The following are the key features of d8.jar: d8.jar download

You might find sketchy websites offering direct d8.jar downloads. Do not use them. These files could be:

Always obtain d8.jar from official Google sources. java -jar d8

Problem: Error: Could not find or load main class com.android.tools.r8.D8
Solution: Make sure you run java -jar d8.jar, not java -cp d8.jar .... The JAR’s manifest specifies the entry point.

Problem: Unsupported class file version
Solution: Downgrade your Java compiler target to Java 8 or 11. d8 supports class files up to Java 11 (and partially 17 in newer versions). Basic example – Convert a JAR of class

Problem: Needing android.jar for correct linking
Solution: Extract android.jar from an Android SDK platform (e.g., platforms/android-33/android.jar). Without it, d8 cannot resolve framework types like Activity.

To ensure compatibility with older Android devices, specify the minimum API level:

java -jar d8.jar --min-api 21 MyClass.class

The most reliable way to get d8.jar is through the Android Studio SDK Manager. This ensures you get a version compatible with your other build tools.

Locating the file: Once installed, d8.jar is located inside your Android SDK directory: