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D8.jar Download Info

Once you have d8.jar, you can invoke it via command line or programmatically.

One of D8's main features is "desugaring"—allowing you to use Java 8+ language features (like Lambdas) on older Android versions. D8 handles this automatically if the class files are compiled with Java 8 compatibility.

# Download sdkmanager if you don't have it
# Find the command line tools at: https://developer.android.com/studio#command-line-tools-only

Determine which version of Build Tools you need. You can find a list of versions on the Google Maven Repository or the official Android Studio release notes.


1. "Unsupported class file major version" d8.jar download



2. "Unable to access jarfile d8.jar"





3. Missing Dependencies
d8.jar sometimes depends on other libraries in the lib folder (like asm-9.x.jar or kotlin-stdlib.jar). If you move d8.jar to a different folder, it may crash.





d8.jar is a command-line tool provided by Google as part of the Android Build Tools. It stands for "Desugar" and "D8." Its primary function is to compile Java bytecode (.class files) into the DEX format (.dex files) that the Android Runtime (ART) can execute. It effectively replaces the older dx tool and is the underlying compiler for the Android Gradle Plugin. Once you have  d8


This guide covers how to obtain d8.jar, how to use it via the command line, and common troubleshooting tips.




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). # Download sdkmanager if you don't have it


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.


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/
D8.jar Download Info