Hey there, I totally get how frustrating it is to hunt for a smooth Smali-Java round-trip workflow when you're knee-deep in app modding—been there, done that! After digging through countless resources (including XDA threads that often leave out critical details), here are the most practical, streamlined methods I’ve used to get this done reliably:

Smali to Java (Decompilation) #

These tools will turn Smali code (either from a full APK or individual files) into readable, editable Java:

• jadx (My Go-To)
  This is the most user-friendly and accurate option for most cases. Here’s how to use it:

  1. Download the latest jadx release and run the GUI version (jadx-gui).
  2. Drag your APK directly into the window, or import a folder containing Smali files (jadx will automatically parse the directory structure).
  3. Once loaded, you can browse the decompiled Java code, right-click any class to export it as a .java file, or even export the entire project as a Gradle project for easier editing later.
  4. Pro note: jadx handles most obfuscated code and Dalvik-specific constructs better than older tools, so you’ll get fewer unreadable blocks.

• apktool + dex2jar + JD-GUI (Legacy but Reliable)
  If you need to work with individual Smali files or want more control over the decompilation process:

  1. Use apktool d your_app.apk to extract the APK and get the Smali files.
  2. Locate the classes.dex file in the extracted APK, then run d2j-dex2jar classes.dex to convert it to a JAR file.
  3. Open the JAR in JD-GUI to view or export the Java source code.
  4. Caveat: This workflow has more steps, and the decompiled Java might have more syntax quirks to fix before editing.

Java to Smali (Recompilation) #

Turning edited Java back into Smali is trickier, but these methods will get you there with minimal hassle:

• Android Studio + Smali Toolchain
  This is the most reliable way to ensure your edited Java compiles correctly to Smali:

  1. Create a new Android Library module in Android Studio.
  2. Copy your edited Java code into the module, making sure the package structure matches the original Smali files exactly (this is critical—mismatched packages will break the app).
  3. Compile the module (Build > Make Module). Locate the compiled .class files in build/intermediates/javac/debug/classes/.
  4. Use the official smali.jar tool to convert the class files to Smali:

     java -jar smali.jar assemble /path/to/class/files -o /path/to/output/smali
     

  5. Replace the original Smali files with your newly generated ones, then repackage the APK with apktool b.

• Direct Java-to-Smali with smali.jar
  If you don’t want to use Android Studio, you can compile Java to class files manually and convert:

  1. Compile your Java code with the Android SDK’s javac (make sure to target the correct Android API level):

     javac -cp /path/to/android-sdk/platforms/android-XX/android.jar YourClass.java
     

  2. Convert the compiled .class file to Smali using smali.jar as shown above.
  3. Important: Avoid using Java 8+ features (like lambdas or default methods) unless your target app supports them—Dalvik might not handle them correctly.

Pro Tips for a Smoother Workflow #

• Add Tools to Your PATH: Put jadx, smali.jar, baksmali.jar, and apktool in your system’s PATH so you can run them from any terminal window without typing full paths.
• Fix Obfuscation Quirks: If the original app is obfuscated, the decompiled Java will have variable names like a, b, c. When editing, keep the class structure (method signatures, field types) identical—only change the logic inside methods.
• Test Early and Often: After replacing Smali files, repackage and install the APK to test immediately. Small changes (like mismatched method names) can crash the app, so testing saves time.
• Use jadx’s Gradle Export: Exporting the decompiled code as a Gradle project lets you edit in Android Studio, which will catch syntax errors before you even try to convert back to Smali.

Hope these workflows make your app modding go smoother—let me know if you hit any snags with specific cases!

内容的提问来源于stack exchange，提问作者Shiraz Ahmad